Microsoft is <A HREF="http://news.zdnet.com/2100-3513_22-5601580.html?tag=zdnn.alert">beefing up its corporate instant-messaging product lineup</A> with new extras like firewall traversal and collaboration, as it prepares to launch a new desktop communications client, possibly as early as Tuesday. All the development work is an attempt to kick-start a market for corporate instant messaging, which hasn't grown as quickly as anticipated, although a growing number of businesses are increasingly making use of popular desktop IM clients.