iphone - Mobile peer-to-peer connections -

i want make software great if not needed server @ all.

it possible make internet connection between 2 mobile devices?

does have clue on need research iphone, android , blackberry?

you can direct connection udp or tcp encounter logistical problems. example if on same wifi network good. if 1 phone on wifi network nat'd address , other on public address, have problems since private nat'd address not route-able. if phone private knows ip of public address phone,the private ip phone can make initial contact.
why people use server have 1 central location meet , connections can established.