Does your company use SIP?(I suspect they do)
Do any of the M$ Messenger apps support SIP?
Is your iPhone on your companies network to even talk to the SIP/Messenger servers?
Much more detail needed, but I'm assuming you mean they're using Windows Messenger tied to the Exchange Messenger service that was built into Exchange 2000, and removed in 2003. If that's what you mean, then no.
Does your company use SIP?(I suspect they do)
Do any of the M$ Messenger apps support SIP?
Is your iPhone on your companies network to even talk to the SIP/Messenger servers?
Unfortunately, I discovered the work exchange server that they are using is only for Verizon (blackberry) users, so I was unable to push work emails through my iphone. Does this mean its a no-go for the Windows Messenger idea?