Hello,
As far as I know, there are programs available that can do this one-to-one. But to my knowledge, no such program available that can do one-to-many. There are many challenges that need to be overcome to do such project.
1) Difference between your screen's resolution and target machines resolutions. Not all target machines will be running on same resolutions. Thus, mouse movement and clicks need to approximate to your screen. Therefore, it will be approximate, not 100% exact but close to it.
2) Your and target machines can have different internet speeds. Some may lag behind. Program can relay commands to target machines and then indicate to you (through system tray icon beside system clock) that all commands were processed.
3) Theoretically, due to limits of TCP/IP, you won't be able to connect more than 65535 target machines. Hopefully, you won't reach that limit. But actual limit will be more lower but you still can connect to thousands of machines simultaneously. But it largely depends on your machine's computing power and your internet up-link speed.
There are many minor and major challenges for this project that will need to investigated and solutions need to find for them. That's why I quoted for 40 days in my bid.
I'll write this program in VB.NET 2010. It will be multi-part program. "Server" will be installed in your computer and "clients" will be installed in target machines.
Please message me to discuss details.
Regards,
RawalVW