Shoutbox

As far as i'm aware,
if you have a seperate sound card installed, MSN will detect in in the "Audio/Video Setup Wizard". If your headphones are attached in here, you can just select the audio to be routed here. Although, i am not quite sure if this will change it for your computers default settings (and Windows Media Player included).

If you only have one sound card (on the motherboard) which has two headphones ports then I think you shall just have to plug the headphones in when needed. Like my PC, this will then cut off the 2.1 speakers and reroute the electrical signals to the headphones.

Seeing as sign in sounds are part of Windows after installing MSN messenger, they cannot be altered seperately so the default Windows settings for sounds apply to these. They will play either through the speakers or through the headphones depending if they head phones are plugged in.

Sorry, Hope this helped,
Hyped