I spent an hour or so this morning looking into Web-based Java desktop sharing services, and had the best luck with one called Elluminate. I believe the original purpose is educational, for online classes and so forth. It allows remote desktop control under certain circumstances, which is what I was originally after, and doesn’t require port forwarding or other technical points.
It also has some file sharing, whiteboard displays, audio and multimedia options. In that sense it’s a bit overkill for what I need, but one never knows when those frills might come in handy.
It’s also free for up to three connections at a time, which means I could conceivably host more than one person in a “session.” Why would I want to do that? Beats me. But it sounds cool.
One thing that I need to remember for the future, is that my fastest machine is still a great deal slower than the machine I was connecting to. I was getting some serious lag while waiting for the desktop to refresh, and didn’t figure out why until I realized that the distant machine had a lot of desktop effects enabled.
So the moral of the story is, turn off Compiz when connecting a Pentium III to a dual core machine.