as I've no iPhone I hope to get some help here:
There's a server that allow remote access (RDP, VNC),
A client (iPhone) should connect to this server and print local (also a portable printer for iPhone is needed) from a server application.
With a windows RDP isn't a problem for sure but I know less about the iPhone.
What client software for the iPhone can do that (I found: http://itunes.apple.com/us/app/2x-client/id401103105?mt=8
What is a good portable printer for the iPhone toi use with?
Maybe there's also a solution for Andoid?