What is the proper way to add a field such as "MSN Instant Messenger" into the profiles?

Thanks!

Well, hopefully you've received an answer since your post, but the way most people do it is like this:

1. Go into the /admin control panel of your forum.
2. Under "User Profile Fields" click on the "Add" option
3. Fill out the form with the MSN Handle information you want your users to see.
4. In your UserCP add your MSN handle and that's all there is to it!

Hope that helps!

im making a hack for this, expect it in about a hour

Looking forward to it. :)