using xbee as a uC

i want to know if i can use the XBEE UC to manage some simple tasks like activating a relay
thank you

If you use the 802.15.4 XBee modules and the DIO line passing function or the remote AT command functions you can. Otherwise you need to either use the Programmable versions of the XBee modules and write the necessary code for the 2nd processor or use an external processor to perform the necessary function.