HD - I've had a look at some of your images and agree they don't seem very sharp for some reason. However, I've seen plenty of pretty exceptional ones taken by a Canon 20D; so, it may just be either a setting issue or perhaps a focus fault with your actual camera.
If you have juggled all the settings and checked your taking photos with the correct shutter speeds for the situation and lens fitted; and still no joy - It may be time to let Canon check it out.
I can't advise further as I'm a Nikon user myself! Nikon D70 at the moment but, looking to upgrade to poss the D200 at some point.