A few more specific thoughts on the matter:
Were there any legal challenges that a woman faced when plying her trade?
What was the social stigma towards a prostitute? How about a john?
How much of a difference would there be for a lower class working girl compared to one with a higher end clientele?
The Victorian Era spans a very long time, so how much of a change was there between the early period, and the waning years?
The problem of prostitution was one of the most fascinating social and legal problems in 1800s Britain. (fyi, PhD, with expertise on history of sexuality/Victorian history--I wrote my dissertation on Victorian prostitution)
Legal challenges The classic touchstone regarding the legal regulation of prostitution would be the Contagious Diseases Act of 1864. In an effort to curb the sexually transmitted infections that ravaged the military, the CDA of 1864 basically allowed any police officer to detail a woman suspected of prostitution (usually determined by "looks"), have her medically inspected and detained in a lock hospital for treatment. This legislation, though later repealed, effectively was an attempt to legalize and regulate prostitution, but that, in and of itself was a massive problem, primarily because there was no way of formally registering and monitoring prostitution! (check out Judith Walkowitz's Prostitution and Victorian Society: http://books.google.com/books/about/Prostitution_and_Victorian_Society.html?id=3wbfmH9L9qoC) EDIT: This was overturned because, obviously, this was wicked discriminatory to women. Reformers like Josephine Butler lobbied hard to get this off the books. There are accounts of women committing suicide because they were unfairly targeted, and there was no police accountability.
Social stigma The fascinating thing about prostitution is that it was not a set definition, but incredibly fluid term. The ways people understood prostitution within popular culture, medical treatises, and social studies varied over the course of the century, in some startling ways.
In the early 1800s, specifically in 1809 and 1812, evangelical tracts sought to identify and punish prostitution. Within these tracts, prostitutes were called "vile jezebels," "serpents" who would lie in wait to ensnare the naive sons of the middle class. In 1809, a silk merchant and Independent congregation churchman, William Hale, wrote “An Address to the Public, on the Dangerous Tendency of the London Female Penitentiary." This is where the vile harlot stereotype can be found. While repeating many of his initial arguments, Hale’s 1812 Considerations on the Causes and the Prevalence of Female Prostitution, further elaborated his conceptualization of prostitutes and his favored means of suppression. Irrevocably, prostitution was a moral evil, the prostitute a willful sinner, and eradication of harlotry was within the realm of possibility. Said Hale on the first page of his tract, “we find no evil so extensive, so frequently repeated, or so destructive in its consequences, as the crime of prostitution. Whether we consider it in a moral, or in a political, point of view, it is fraught with the greatest calamities that can befal [sic] the individual, or the community; and any successful measures to reduce the sum of this most ruinous species of depravity, must be considered of the highest importance to the well-being of both.”
However, the Industrial Revolution had a hand in changing the definition of prostitute--social studies in the 1840s and 1850s posited that the prostitution was more a product of the grinding industrial poverty and influx of young women to the cities, rather than a moral shortfalling. Reformers like Ryan, Tait, Logan, and Talbot were guided by the ideologies and anxieties of the evangelical who wrote about prostitution before 1837. They worried for female purity, family purity, and societal purity. Specifically, Talbot’s iconic trope of the “fallen woman,” is a description of prositution that encapsulates the anxieties over womanhood in this period: “The one fatal step which has brought shame upon her head, has banished shame from her heart. The first false movement leads to crime; crime blunts the feelings, and hardens the heart; and, afraid to return to the home she has forsaken—no friendly hand being extended to save, the whole moral principle speedily becomes obliterated; she plunges deeper and still deeper, into vice and iniquity, until she is irrecoverably lost.”
Finally, let me skip forward to 1885, when one of the most radical changes in the debate over "prostitute" took place. William Stead, the editor of the Pall Mall Gazette, orchestrated a sensational media campaign to help pass a law that raised the age of consent from 13 to 16. In "the Maiden Tribute of Modern Babylon,", Stead bought a 13yo for 5 pounds, a crime that would land him 3 months in prison (but only because he had gotten permission from the girl's mother, not her father). It didn't matter. Stead's campaign got the law passed through Parliament, and offered a whole new definition of prostitution--suddenly, the prostitute was the victimized, under-aged girl. While there's been a lot of debate about how Stead went about his reporting, there's no question that he galvanzied public support, and created an indelible image of the virginal girl sacrificed to the predators of London.
As to men, My Private Life is probably one of the best views into the relationship between women and their johns. This anonymous (largely attributed to Henry S. Ashbee, though) account details hundreds of interactions between a man and servants, prostitutes, and other women. While there's no way to truly account for it's truthfulness, it's probably the closest thing we've got to a fairly compelling account of HOW men and women engaged in the system of prostitution. Additionally, Steven Marcus's "The Other Victorians" is a great look at how pornography of the Victorian age represented prostitution and sexual ethics.
Regarding social stigmas, prostitution was viewed as an awful crime for a woman to commit. It contradicted all the beliefs about Victorian women, such as that they were innocent, fragile and moral. Furthermore, women were not supposed to be aware of their sexuality. It also had strong links to alcoholism, which was another social issue, as prostitutes were often found in public houses. However, as much as it was frowned upon it was actually regarded as fairly normal. Men, from all classes, regularly visited prostitutes. Also, working class women earned a lot more money through prostitution, eventually it was actually seen as an inevitable phase that women from the working class went through.
Contagious Disease Acts were introduced to tackle the venereal diseases caught from prostitutes, however, this was more of an attempt to protect the men from catching the diseases. Also, women were put into 'Lock Hospitals' which were badly run and essentially trapped the prostitutes, as the name suggests.
Crime, Policing and Punishment in England, 1750-1914 by David Taylor. Broad but informative.