Limiting Windows Live Messenger

Our company has been using Windows Live Messenger for the employees to communicate with each other. Unfortunately some of the employees are abusing it by chatting with personal contacts during working hours. Does anyone know of a way for us to block specific contacts? Or to just have an allowed list of contacts that excludes all others? Parental Control software that is capable of that is not out of the question as we are also looking to limit internet usage.

I am also willing to look at another IM client if there is something we can use that I can control the allowed contacts on. Thanks.

 

Hello Jack.
Here's something to get you on the right track. Note that I have very limited experience with this type of software, so unfortunately I can't recommend anything specifically. I guess you'll have to try a couple of them.
Keep us updated.

 

Google Talk for domains allows you to limit users.
We use Microsoft Office Communicator which is a LAN only sollution (we use it with active directory).
Install your own JaberServer on your LAN and connect with any decent IM client like Pidgin, Trillian, Miranda etc