BB is a very small, very simple webcam / security camera viewer for Mac OS X. Just give BB the URL of an image and a refresh rate. The latest image will always be visible on your desktop. You can choose to display the image in a normal window, always-on-top, or at the desktop level (below everything else -- even icons, but stays put during Expose). BB is easy on your Mac, and rock-solid stable. It only does one simple thing, but it does it well!
BB is nag-free donation ware. You can use it for as long as you like, never pay for it, and never deal with nag screens or timebombs. The author does request that if you find BB useful, you consider making a small $5-10 contribution to support future efforts.
("Easy on your Mac" means BB takes about 3MB of RAM and uses less than 3% processor for a 320x240 image that updates once per second from a server on the same 100MB LAN segment. YMMV, of course!)
This review was originally posted on VersionTracker.com. This is a nice start, but it should not have been released as a 1.0 - it feels a bit like a beta with one little but noticable bug (double 'help' item in the menubar for me), and lacks a few features as mentioned below. But it is a good start, it works, and as it is freeware, I have to give it 5 stars.