The main primary sources for the Classical Greek period are Herodotos 7.153-170, Diodoros of Sicily's Library of History (mainly books 14 and 15) and Plutarch's Life of Dion and Life of Timoleon. Diodoros is a late source, but as a Sicilian native he took care to include Sicily in his universal history whenever he could, and he gives us priceless glimpses of his lost sources, including the histories of the Sicilian Timaios.

First we have to know to what ressources do you have access. Are you in secondary school (the french lycée I presume) or do you have access to an university library. Like it or not the most essential books are in german. I barely know german myself but I still had to put my nose in those encyclopedies because they gather together source informations that are otherwise split in too many specialized works. So the first thing I would do would be to check to entry for Sicily in the Realencyclopädie der classischen Altertumswissenschaft(RE) there you would have all the necessary references to the sources gathered together. If you want a shorter but more revised text, check Der Neue Pauly (DNP), it's basically the same all encompassing encyclopaedia but more recent. Note that as sicily is at the letter S the article in the RE would be not too old (it took nearly 80 years to publish it)

Now for short you can already almost forget about carthaginian sources except if you have to ckeck for epigraphic documents but I never used carthaginian epigraphy before.

To begin the main course: one of you main sources would be Polybius. I personnally bought a complete french version of his text to read it quitely and then check for scientific editions of the Presses Universitaires de France later (with the greek text, the variants in the manuscripts and all of that). In Polybius you will find our main source on the roman conquest of mediterranean. I have personnaly focused on his depiction of Philip V of Macedon and the Seleucid Antiochos III, two very important kings but with only a minor role in the history of Sicily. There are holes with entire books missing but they are hopefully complete by the roman history of Livy. We have the beginning of it and a few books around the second punic war and the syrian war (Rome vs Antiochos III), as he narrates year by year there should be things about Sicily there.

Don't forget Cicero and the Verres scandal, a governor of Sicily which looted the province for himself. He made several discourses only against him.

Look in the history of the civil war by Appian for information on Sextus Pompey, the son of Pompey the great, he ruled Sicily and nearly starved Rome controlled by the triumvirate.

Beyond in the imperial period Sicily cease to be an interresting place for me...I am sure there are mention in later authors, escpecially in the late empire but I can't help you without more extensive researches, again for a panoramic view, check the RE.

If you want epigraphic sources, use the Inscirptiones Graecae (IG) number XIV for Sicily for greek and the Corpus inscriptionum Latinarum (CIL) Volume X, but it's from the late XIXth century and in latin... so...

If you want to read the texts: [http://agoraclass.fltr.ucl.ac.be/concordances/intro.htm](the university of Louvain (la neuve) can help you) note that those are quite old translations.

Oh! If you're looking for secondary scholarship on this topic, see if your university has access to L'année philologique (www.annee-philologique.com). It is extrodinarily helpful for research -- I am currently using it to construct my reading lists for exams. WorldCat (worldcat.org) may help you find other sources in your area.

While our users may be able to help you out here, we hope that you also will take the time to check out our six-part series, "Finding and Understanding Sources", which should hopefully prove to be helpful for you as you continue in your research.