What is it?

mqsvc.exe is the executable file of the microsoft message queuing service.

What does it do?

Microsoft Message Queueing (MSQS)?provides guaranteed message delivery, efficient routing, security, and priority-based messaging. It can be used to implement solutions for both asynchronous and synchronous messaging scenarios.

More info:

Everything you ever wanted to know about MSQS can be found at [url=http://www.microsoft.com/windows2000/technologies/communications/msmq/default.asp]microsoft.com[/url]