My preferred chat client is Adium (adiumx.com) for Mac OS X. This program allows you to chat with all the major chat services. For each chat service you can have multiple accounts. All contacts are synchronized with your address book. When one of your contacts updates their buddy icon it is updated in Address Book.
When I tried to use my ExchangeLabs Live ID in Adium, it did not work. Every time I tried to log in, it kept stalling on the downloading contacts list step. I though that was strange since I did not have any contacts in my account.
The solution was to log into the chat account using the MSN Messenger application (available from Mactopia), login one time, add a new contact, then quit MSN and erase it from your hard drive. The last step is optional but I do not intend to ever use it again. Now Adium can log in to my ExchangeLabs chat account just fine.