It's now possible to connect to the net through your cellphone. Throughput is maybe 9600 bps after alls said and done. If a laptop's too big, you can use an organizer.
Some models have terminal emulation and xmodem capability.
A maybe 12x40 character real screen maps to a 25x80 virtual screen - painful, but not impossible to use. You can draw pictures and send faxes, too.