Why not try an Arduino Fio? I've got one that I connected the SLEEP_ON signal from the xbee to D2 on the Fio and I'm using xbee cyclic sleep mode and putting the fio to sleep waiting on a rising edge interrupt on D2 every 10 minutes. I'm still working on the software but I'm hoping to get a couple of months from a 1000mAh LiPo battery.