Once you connect two machines with localtalk, they are networked.
It doesn't matter if there is a connection to "the net".
As for speed, 230,400 kbps of localtalk is slower than ethernet,
but it is faster than most CU-SeeMe transmission rates I have seen.
(It is also packet based. Mild flame: Why do people who admit to
not knowing things feel the need to answer questions about them?)
Alan