I've made a networking unit (TCP and UDP client/server classes) capable of multiple connections, with simple interface. It's asynchronous non-blocking.
You can download the sourcecode with some examples at:
http://members.chello.sk/ales

NOTE: LNet requires a very recent FPC version since there were some changes in sockets.pp file. You can ether get the CVS version of FPC or wait for 1.9.6 which should be out soon