The easy way is to use GameKit, good starting article at :
Though what I *really* want to do is create an ad-hoc wifi network… So far it seems that apple has restricted devs to only access existing wifi networks (IE you aren’t allowed to create your own ad-hoc network on the iphone). I’m assuming this is a “feature” designed to make it more difficult to find a way to tether your iPhone to another device.
Oh well. Buzzwordingo should have chat capabilities soon enough.