I had the same question before I bought a 52x52cm track bike. I raced it for a year and found it uncomfortable. Raising the seat and using a longer stem just made things worse, my knees hit my beer belly and the long stem made the handling "whippy". It's important to hold your line when riding in a group like that.
I think the other poster is riding a frame that is too big for him. I am 5'9" with a 31 1/2 inseam and ride a 54cm track bike and a 55 road bike. But my calculated size is 53.6.
Here is a link to a site that gives formulas you can use to find your true size. Frame size can be calculated by measuring your inseam x .67 and converting to centimeters.
http://www.coloradocyclist.com/bikefit/