MSN used to have chat rooms but the closed them down because it was too easy for children to meet paedophiles (or something) ... the best way to meet new people through MSN messenger is to ask one of your friends to introduce you to some other people. They can add you into their conversation so you are having a three-way conversation (or as many people as you like really) and after that you can add them as a contact.
You can join a few msn groups and if you get along well with someone on the message boards or like the sound of them you can ask if you can add them to your msn messenger.
Hi Fairy, I've just found this post again. You have a "passport" off msn for your msn messenger, and you can use this to join msn groups. Find one that interests you, as there are lots of catagories.. relationships, romance, ets, etc