Just got a Dynex 1.3 MP (the DX-WEB1C from Best Buy) to work with Skype on a MacMini 10.4.11.
Keys:
Nothing comes on the CD nor at their website for 1.3 MP and OS X. You have to go to a different, discontinued webcam and download its driver. (I probably downloaded this by mistake, a happy mistake)
http://www.dynexproducts.com/p-459-dynex-desktop-web-camera.aspx
Look for Dynex Webcam:Dynex Driver OS X.10:Dynex Driver OSX 1.01.dmg in the downloaded folder. IIRC, there's a note which says this is only for 10.4.9 and up. Double-click on Dynex Driver OSX 1.01:Dynex Driver Install.pkg to install and then reboot.
Macam doesn't support Dynex.
The video only works on one app at a time. If you're playing with the camera in 'WebCam Support' (an unmarked app, I'm not sure if it appeared after the Dynex or Macam install attempts), it won't show up as a source elsewhere.