From clievideo.com comes Palm Webcam 1.0 — a combination device/desktop application that turns camera-equipped Palm OS devices into a Windows webcam. I gave it a whirl with a Zire 72 and Treo 600 and it worked pretty well with Yahoo! Messenger. (Ahh, the best of both worlds…Palm and Yahoo!)
The video quality in both cases was pretty good with a slight nod to the Zire 72 (which has a better camera than the Treo 600). The speed was much better on the Zire 72 as well: at 320×240 resolution, the app reported 4.9 vs. 1.6 fps on the Treo; for 160×120 the difference was even larger at 1.9 vs 11.6 fps.
I like this solution — a $15 piece of software gives you a new function for your existing device. It probably won't be much of a threat to “real” webcams, but I can imagine it being useful for mobile travellers, for example (no need to bring a separate webcam with you).