I will divide this answer up into short and long answers, depending on what exactly you are looking for. Short Answer: If you are wanting a good summary of the basic events of the Sith Era (and the entire Star Wars Expanded Universe as a whole) then consult Star Wars, The New Essential Chronology, Second Edition, which is out in bookstores now. Long Answer: As of September 2006, there are not a lot of novels out yet that deal with the "Sith Era" (i.e. the time period before Episode I). That is soon about to change with the publication of Path of Destruction: The Rise of Darth Bane by Drew Karpyshyn in October 2006. Now that Episode III is completed, and the Prequel Trilogy is done, Lucasfilm has given the green light for Del Rey to produce novels set in the Sith Age, which will encompass the first 2000 years of Star Wars history before Episode IV. Now, while it is true that Dark Horse comics have covered this time period extensively in the past decade, particularly with the "Jedi vs. Sith" series, I personally did not find these comics that enjoyable. You may like them, but they will be a lot harder to find. You might want to try the Dark Horse and Star Wars websites directly, or consult eBay. I personally prefer the novels, but that's just me, and there are a lot of comics out there that cover the Sith era. One particular novel that we can look forward to next year comes from regular Star Wars author James Luceno, who will be penning a book on Darth Plageuis, who is identified in Ep III as Senator Palpatine's master. Of course, if you are interested in Star Wars books post-Return of the Jedi, than the definitive trilogy to start with is the now-classic "Heir to the Empire" trilogy by Timothy Zahn.

Well There's the Legeand of Darth Bain Book, the Knights of the old Republic Searys for video games and a Few comic searys that are up for reading pluss there are more books on the way im shure

if you love star wars, don't read the "Vong" stories that take place over a decade after the return of the jedi. these aliens who are like organic versions of star trek's Borg, invade the galaxy and ruin everything. and i loved the young jedi knight's series too.