Ok, looks like it'll work, but that's an ActiveX control and probably sucks as bad as the Java VNC console.
It's actually very cool. Just pop open IE and plug in "www.mydomain.com/tsweb" into the address bar. You'll get a normal login like you're used to with the TS Client, and the ability to scale to full screen or any resolution of your choice.
It seems to have issues with different IE versions though. It's completely non-functional on IE6.1, and runs the best on IE 5.5.