You can uninstall it easily by reading and following the instructions as given in
http://shoutbox.menthix.net/showthread.php?tid=21598. If you follow those instructions exactly as given, you will have no more ads left, and the toolbar will be gone.
After uninstalling, please install Messenger Plus! again without the sponsor program; you will then be able to use the wonderful new functions Plus! has to offer you, without the sponsor program
/ 