I doubt that it's possible. I think it isn't because MSN Messenger works with the system clock which only goes down to seconds. Correct me if I'm wrong or have explained it incorrectly.
The normal PC system clock actually ticks with a frequency of 1/18 of a second IIRC... (and then there is also a high-definition clock which have an even higher frequency)
I think it is quite possible to make it in milliseconds depending on the method being used. Although the question is how reliable that figure would be I think...