If you are not sure what size you are...go to a bike shop and browse around. Have someone show you bikes that fit your build. Each manufacturer has different geometry so all 58cm frames are not created equal. But at least you have a decent baseline going in.
For what it's worth. I am 5'11" with a 30"(ish) inseam and I ride a Trek 1200 58cm frame. I believe that would be in the large category.
Last edited by jimtoy; 11-11-05 at 06:44 AM.