There are a few freeware packages out there to do paging.
I am using tpage which worked with a little prodding. I
also found an expect script which will send alpha-num
pages.
After you get a script that will dial your paging company,
you could modify ip_monitor.tcl to send a page when something
becomes unreachable. I've done just that, and it works OK.
You'll need to use the direct "paging central" number for your
paging service, SkyTel calls that service SkyMemo, and the
number is 18007596366.
Hope this helps,
davec