Remote Management and the Classroom?

I have been looking at providing my teachers with remote management options for their classrooms using both payed for tools as well as free options such as iTALC. Has anyone done anything like this for a k-12 environment with ZCM installed? One of the big complaints that my teachers have is the fact that the laptops we have are slow. My fear is that adding additional software like this will cause further slowdown. I don't know if there is a way to provide the function through ZCM or not. So far I haven't seen a useable solution outside of adding a third party option.

Anyone use iTALC in this kind of environment? Any other software that might be helpful for this process. I would be looking at allowing no more then 25 monitored sessions to a single teacher with the normal count around 15 at the most. I have several teachers that are wanting to view student sessions without having to get out of their seat. It would be nice to have additional functionality as well but this is the first step.

Thanks for any advice.

Richard