Why don't you try this program ShixxNOTE 6.net - Network enabled sticky notes program (LAN messenger)
With this program you can send message in note format or via Windows messenger service (NET SEND) to any comp in your LAN. Also you can send note or message to 20 comps with one click. Try it.
Description:
ShixxNOTE is a desktop sticky notes (post-it) program, that allows you to keep desktop sticky notes, and also send them across the network (or Internet) to friends or colleagues. The program runs in client/server mode and transmits messages or notes to selected Shixxnote clients on the network. However, you can also send messages to machines that do not have Shixxnote installed, in which case the program will automatically use the standard XP/2000 Windows Messenger service to deliver the message. It also includes alarm options that allow you to be reminded of selected notes, and support full formatting of font, color and appearance of the notes. Other features include a reply option, emailing of notes, note export, printing and more.