I assume you're interested in ibn Fadlan's Risala, which chronicles his full journey and deals with the Vikings as well as their home society (Rus was the term they used to describe people whose identity is not yet 100% agreed upon--might have been Scandinavians, might not have been). Finding any version of the account online that hasn't been heavily abridged to valorize them further or made into snippets for some academic purpose seems difficult. As far as I know, Richard Frye's translation published by Markus Wiener in 2009 is the first complete one in English, annotated as well. Markus doesn't put out ebooks yet, but he still runs the best house for getting translated primary sources of unusual origin published. I did see, in a search, a document housed at Indiana that claims to be a translation, but it is a .doc file, seems rather short, and was intended to be a course reading so might be incomplete. Prof. Lazzerini's course site, with the link to the file of the text, is here, under number 2. No, I don't know why that webpage font seemed like a good idea either.

If you're interested in a detailed discussion of the account's reliability, the identity of "Rus," and some sources connected to them that isn't behind a paywall, see:

Montgomery, James E. "Ibn Fadlan and the Rusiyya." Journal of Arab and Islamic Studies 3 (2000). NOTE: PDF LINK

[Yes, I omitted the marks on the letters of the title, but it will still get you there. edit: felt it important to put more detail in the article description.]