Wikipedia, dude, you need wikipedia. You can read overviews of the whole franchise, overviews of each series, overviews of each season, there are separate pages for each character, etc. Very handy.
http://en.wikipedia.org/wiki/Star_Trek
Better yet, memory-alpha.org.
Although, I actually enjoy coming here and asking questions instead of using the Internet sometimes. I like the quasi-human interaction, and a lot of other trekbbs members have knowledge from books or personal experience that isn't included on memory alpha.