We're doing it right now where I work. It's tough, real tough. So far, we're targetting IE5.5 (which we can do because we write Intranet applications) and my colleague has managed to build a quite good tabbed dialog box effect, but DOM support isn't quite advanced enough for NS6 or Opera to display it right. Sorry, I don't have a web site to point you to.

Would it be better to use applets or ActiveX controls, or would you just recommend sticking with client/server for now?

Thanks,
John