All the names I can think of suck... technically this forum covers 3 different programs: Windows Messenger, MSN Messenger, and Windows Live Messenger.
"MSN/Windows/Live Messenger" is a little long.
Using both "WL
M" and "Messenger" in the name would be redundant.
Just "Messenger" is too vague - it wouldn't exclude Yahoo and AIM and stuff.
Blah.