I've been thinking about writing a remote file serving system, that will allow you to access files on your PC. The idea is to use file serving for development, then simply change one line of code for release to access files from SD card or DVD instead.
I think the simplest way to achieve what you want is to use TCP/IP sockets. If you take a look in network.h you should see the required functions. The functions are equivalent to Linux sockets, just with slightly different naming conventions. Therefore you can use a Linux reference manual for information on how to use them.
Hope that helps!
Thanks,
cdmac