I am currently (Nov 2006) just running off the wall warts. I do plan on battery power, but will be going with LiPo battery packs to get a greater power density. I have not purchased them yet because I'm still working on selecting and acquiring a wireless IP camera, and don't know what the power requirements are yet. (See Future Plans.)
Assuming that the voltage is below 7.4 Volts, I'll be looking at a "two cell" pack or pack(s) in parallel. Once I have a decision, I'll post the information here.
[To Do: Post updated battery information when available.]