I work at a company in which 500+ employees work remotely. Often we have software outages that are planned and we like to communicate to all employees that these outages are going to happen in XX amount of minutes. I use the DOS command 'msg' to accomplish this. This can be pasted directly into the "run a remote command" task dialogue box.
msg * /time:999 **ATTENTION**SOFTWARE OUTAGE IN 20 MINUTES** **The software system will be unavailable as of 7:15am CST. The expected outage time is 20 minutes.**
This message will pop into the forefront of the end user's display even if the system is at the login prompt. I find this very useful because One2Many will ignore any systems that are offline, thus only the online users will receive the message and because it appears on top of all other windows, it is more effective than email communication.
Note: The /time:999 switch will force the window to stick for 999 seconds. It seems that entering any value over 999 will force the default value and the message disappears after 15 seconds or so. I use this timer in case someone is away from their computer at the time I send the messages.