Canon uses two mounts on it's EOS SLR's they are EF and EF-S mounts. All the XXD (20D, 40D, 60D etc) and XXXD (500D, 550D, 600D) use the EF-S mount. So does the canon 7D. So if a lens works for one of these camera's it'll surely work with the others too.
5D and 1D uses EF mount. They have specific lenses with EF mount.