“Browser Cam creates screen captures of your web pages loaded in any browser, and on any operating system, so you’ll be 100% sure your web pages look good-and work right-on any platform.”
A handy tool — $39.95 / month though. Also they don’t seem to have all browser/operating system combinations available. XP is not there at all. Still worth the trial. I’ve used a few times with some helpful results.
CSS3 For Web Designers Paperback + eBook A Book Apart
Bulletproof Web Design Third Edition New Riders 
Handcrafted CSS Book and DVD New Riders 
Web Standards Solutions Special Edition Friends of Ed 
Dribbble What are you working on? 
Instapaper Icon design