Here's some of the most informative stuff I've read on Palin's background so far:
Fred Barnes had an informative Weekly Standard article last year about her rise.
Her Wikipedia page was very thorough (assuming it hasn't been vandalized since I read it).
And here's an amusing article on Frank Murkowski's state jet, which Palin had the state of Alaska sell on eBay. Murkowski bought it with state money after the Department of Homeland Security turned down his request for money.
I love that Palin has been willing to take on all those pork-barrelling corrupt Alaska Republicans like Murkowski, Don Young, and Ted Stevens. According to Barnes she line-item vetoed 13% of Alaska's capital budget in her first year in office.