Lens Question

I'm thinking of getting a Canon 20D and already have a 35mm Rebel. I only have the lens that came with the Rebel. Instead of getting the lens that comes with the 20D, I was thinking of getting a telephoto lens. Can I switch the Rebel lens and the telephoto? Do digital and 35mm cameras use the same lenses?
Thanks for your help...I'm still learning a lot!

Also, would you suggest the 20D or the digital Rebel? I'd hate to spend $1000 on the Rebel and then decide to upgrade. I thought I might just skip the Rebel and go straight to the 20D. Any suggestions? Thanks again!

Canon AF cameras use the same lens mount regardless of it being digital or film, so you'll be fine using your Rebl lens on the digital body. I think most here would recommend the 20D over the digirebel. :)

Regarding choosing the drebel over the 20D depends on what you plan to do with it as they are very different cameras. If you are working on a limited budget as I am, maybe get the drebel and some good lenses. The 70-200 is a good starting tele, and a good wide to mild tele zoom or a 50mm 1.8. Once you hone your skills, and figure out what you what type of photography you want to do, then you can upgrade the camera to one that fits your needs. That is what i did. I started out with a Rebel Ti, and bought good lenses, and after 2 years and 270 rolls of film later I upgraded to 10D. Seeing a bag full of white L lenses and primes next to a rebel is a funny sight.