Stupid Bicycle Question

Okay, I decided that my gift for myself for making it to Onederland is going to be a bicycle.  I live very close to my work and I'm debating doing the green thing and bicycling to work.  However here lies the question at the root of this post, how do you know what size bike it right for you?  I haven't owned a bike since I was like 12 years old and my parents bought it so I have no idea what size I should get.  I know they come in like I think 24", 26", etc. and I think that's the wheel size.  So if anyone knows of any "rule of thumb" for this I'd welcome the advice.  Oh, and by the way I'm a short 5'3 if that helps, thanks in advance!

I would suggest going to a bike shop like Performance Bike, where they are professional and can fit you perfectly on a bike that will work for you.  They all will service the bike to keep it in top notch shape. Rob

Def. go to a bike store.. not Wal-Mart or Target. They can determine what type bike you need (pavement, trails, mix), what size frame you need, and make the necessary adjustments to fit *you*. We got Raleigh bikes not too long ago.. I can't wait to start riding again, but have to wait until my little-ittybit is a bit larger so he fits in the harness on our bike trailer.