We've had a 300D for a while now, and I think it is really good. As Tim says the 350D is a little more compact and higher pixels, but a more money.
Personally I'm not too sure that the 350D being smaller is a good thing. A friend of ours has the comparable Nikon, and IMHO it is not as easy to use as it is a little smaller, and, I don't think it takes as good a pic as the Canon.
In short a very good camera, which is easy to use and takes good quality pictures. You definitely won't be disappointed.
Matt