Opposite to dialing for connection query

I'd like to get software that would answer the phone so that to the caller
it would appear they've connected to the net, e.g. answering pc would be
running various servers.

Sort of like a mini ISP to just the one address.

The reason is I'm very rual area and just "experimenting" with friends
calling into me directly rather than thru an ISP as most have no idea how to
use a more traditional comm package for one on one connection.

Any help, pointers, software resources etc. appreciated.