The 350D is a great Astrophotography Camera. Its the best bang for buck right now and replaces the 300D that used to have that titile. best Thing about it is the USB2.0. RAW images download to PC in about 4 seconds. JPGS even quicker. Ths makes remote control of the camera fro eclipse photography a dream.....
The Canon DSLR's are by far the leading DSLR for Astrophotography. They have lowest noise sensors, more accessories and more software support than any other camera. (sorry Nikon, Pentax oweners etc...) but its just the facts....
There is not much need to go to its big brother the 20D. Next step up would be the 20Da but its hard to get in Aus and very pricey in comparison.
Check out the Yahoo Digital Astro Group for photos from this camera.
http://groups.yahoo.com/group/digital_astro/
Best regards
Chris Venter