Not one, but two - primarily so that I can keep an eye on her while I'm out, but as a bonus, family and friends can also watch, via a webcam server I run. I also set it up to automatically record the output of both cameras in 15-minute chunks, with any footage older than two days being automatically deleted, so keep diskspace requirements down. If you're interested, you can see the cameras (and possibly, the lizard) in action:
Live uromastyx webcams!
From the technical side, the webcam on the left is a USB-powered Microsoft Lifecam VX-3000, connected directly to the server box, while the other is a cheapy composite-connected pinhole camera going to an input on a TV capture card. The serving software is WebcamXP Pro.