Among other fixes and improvements this update includes iChat support for USB Video Class webcams. This is good news for me as my 12" PowerBook does not have built-in camera and I do not have DV camera with Firewire connection or iSight as previous versions required.

The problem now is that there is no proper list of suitable webcams available anywhere. But with some searching I found some discussions about this issue with some hints:

Apple support discussion forum

List of Logitech webcams - those with UVC support should work. There are two versions of same model in some cases so pay attention on serial numbers.

And finally - I have read from various sources that Microsoft Xbox Live Vision Xbox 360 camera works as well. Widely available this might be a decent solution if you do not have great angst against Microsoft.