Grom's Homepage
My favourite site would have to be Dr Karl's Homepage. Dr Karl goes live on TripleJ at 11:00 AM Thursdays, Australian Eastern Standard Time. You can listen to tripleJ online with RealPlayer here or if you live in Australia find the frequency at Listen to TripleJ
HowStuffWorks - Find an answer to almost everything about how stuff works.
Science FAQ - Answers to common questions on ABC science forums.