net send for win2k pro?

Ok, i have used net send for winnt at my school. But on my home lan we use windows 2000. Is net send built in? or do i need to install it? Also, if it does have it, is it possible to send net send messages to other networks? like say i want to send a message to stud_pdc on a certin network called domain.com. Is this possible?

p.s. im new to nt and win2k. (i like linux 😀 )