Hi geezer3
There are a lot of cool projects you can do with an Arduino!!
your xbee idea sounds cool. (Arduino XBee Shield - DEV-08471 - SparkFun Electronics).
There are 2 types of xbees... libelium's manual might help http://www.libelium.com/tienda/catalog/images/arduino/series2-digi.pdf, I think the xbee will be the best arduino accessory for your project.
You might also like some of the adafruit shields Arduino, Shields Products Category on Adafruit Industries
I've done a couple cool projects, you might also like, Antipasto Hardware Blog: Processing ported to an Arduino + TouchShield ported from Processing