winpopup can still be used to communicate with Win2K/XP, and 2K/XP can communicate back.
Say if you have an ME machine called upgradepls, and an XP machine called MEsucks. To communicate from upgradepls, open winpopup and send any message you like to MEsucks. This will popup in a message box on MEsucks' desktop (it is the same service that aggreived SI
here).
To communicate back, press windows key +r on MEsucks to get the run dialog, then type
net send upgradepls insert message here
Assuming they still have winpopup open, they will get a message back in it as if it was from a winpopup client. net send is fantastic in a 300 computer NT network with obscure computer names :O]]
(but don't do net send * if you don't want to get in big trouble)