Knowing when a packet arrives

I want to know if it is possible to activate a pin whenever a packet arrives to XBee.

My idea is to activate a pin which use an interrupt in arduino to use some functions…

I read something about pin 6 but I think this is pwm and I don’t know if I can use it as 1 or 0…

try this:
http://www.digi.com/support/kbase/kbaseresultdetl?id=2188