Thanks for your reply wave. Yes, I want to control the camera from a PC.
I was hoping someone would say "yes, you can do it with a Canon"!!
As luck would have it I already have a 350D. If that can do the job then great! I have a whole load of Canon software (ZoomBrowser, CameraWindow, Digital Photo Professional, RemoteCapture) etc etc but not really sure where to start. I guess RemoteCapture might be a good place. I'm at work right now and so don't have everything in front of me. Looks like I might need to ask a different question - how to do on-demand capture on Canon 350D.
The majority of modern DSLRs will perform some kind of software-driven remote control. Nikon and Canon are prime examples, but the likes of http://www.phaseone.com/Phase%20One/...ure-one-6.aspx also offer a solution that also gives an amount of functionality for portable devices to trigger the camera.
The Canon website only seems to have updates rather than fresh installs. And of course I can't find the disks that came with the camera and so updates are no good for me. This seems to be a common problem. I had a bit of a look around last night and eventually found a full install for EOS Utility. Will give it a go tonight. What I'm really hoping for is that the Canon software will include DirectShow filters to control the camera. If it does I can write my own software to make it work exactly how I want.
Thanks everyone. If I get this working I'll post some details of what I did, it might be useful for someone else.