Linux to XP, "net send" messenger possible?

Hello everyone. Thank you all for the help with iptables to block a LAN
computer access to the Internet. The CLI command worked very well and
cron does such a great job with running it on schedule, both to block
Internet and then to restore the Internet. Now I would like to "pretty it
up a bit" by sending a windows messenger service message to the LAN
computer that Internet access will end in 5 minutes, to give the
individual a chance to finish up, prior to losing the Internet
connection.

I can send a message to any MS computer on the LAN with the net commands,
run in a command prompt window as such:
net send 192.168.0.2 Hello there, nice to see you.
or
net send paula Hello there, nice to see you.

Either of these commands, run in the command window "cmd.exe" will send
the message "Hello there, nice to see you." to the same computer, in a
very intrusive popup box, where you can read the message and then press
the OK button to dismiss the window. I have the NAT address as well as
the computer name in my windows hosts file. Here is a list of the net
commands and what they do:
http://tinyurl.com/s5862

Is it possible to send net commands from a linux computer to a windows
computer on the same network and if so, how is this done? I would really
like to do this as a CLI command as I would like to incorporate this into
a shell script that would first run the net message command to inform the
user that Internet connectivity will stop in 5 minutes, and then when the
5 minutes has passed, stop the connection with the iptables command that
I was given here. Currently, I run the iptables stop Internet command via
cron and then cron will restore Internet connectivity at the designated
time. This works very, very well, thank you Klazmon and everyone that
helped. The commands that I use are:

iptables -I FORWARD 1 -s x.x.x.x -j DROP
(To stop Internet connectivity on the machine.)

iptables -D FORWARD -s x.x.x.x -j DROP
(To restore the connection later.)

So is it possible to send popup messages to another MS computer or all MS
computers on the LAN with Windows Messenger Service? How can this be
done, is there some sort of program or utility for this? I am using
Fedora Core 3 on the linux server/firewall/gateway currently, will
upgrade to Fedora Core 5 as soon as I am able to get another 200Gb or
better hard disk.

Thank you all for your help and genuine concern, this is a very good
Usenet newsgroup.

Cheers,
--
~Ohmster
"Read Ohmster" in subject, bypass spam filter.
ohmster /a/t/ newsguy dot com
.