connecting to a LAN

[Ronnie]

hi, Im trying to connect my linux machine to a LAN (actually i dont know
if it is already connected or not) the LAN is made up of a lot of windows
machines and eventually i want to have it so two (or more) linux machines
will be connected together via the LAN for clustering purposes.   How do i
know if im connected to the LAN and how do i go about finding the other
machine?

thanks,
Ronnie