XFire is free......All Seeing Eye isn't, if you want an extended friends-list (ie. more than 5 people).

Have a look on the Servers tab in XFire, expand the "All" section, and see what games show up in there......if the game you're trying to play doesn't show up in there (and a hell of a lot of my games don't), then the "Join Game" option will be disabled.

I've never used the facility, so have never looked into why it doesn't work for some games......might be worth bringing up on the XFire forums.