Lioncourt.com reported a few days ago:

Microsoft released Microsoft Messenger for Mac 7.0, the latest version of their popular instant messaging client for the Live Messenger and Office Communications services. Unfortunately, Microsoft apparently paid little or no attention to accessibility.

I haven't tested this myself, but it seems that making Messenger accessible to VoiceOver users would have been very little work for the Microsoft programmers. It's sad that they didn't bother to follow the programming guidelines for writing accessible programs.

I suggest that those needing an accessible program try the excellent Adium client for MSN/Live messenger chatting. Unfortunately there's no accessible replacement if you need to use Microsoft Office Communications. For those who need that functionality, I can only reiterate Josh's suggestion to contact Microsoft through their accessibility site and request that they remedy this.

Website: Microsoft Messenger for Mac 7.0 Released without Accessibility

- Ricky Buchanan

Adium is a fast and free instant messaging client which supports AIM, ICQ, Jabber, MSN, Yahoo!, Google Talk, Yahoo! Japan, Bonjour, Gadu-Gadu, Novell Groupwise, and Lotus Sametime. Adium supports beautiful WebKit message display, tabbed messaging, encrypted chat, file transfer, and more. Give it a try; you won't look back.

Significantly for users with disabilities, the Adium X version 1.2 is now properly accessible to VoiceOver so you won't have to guess who you're talking to. The Adium team care about accessibility - when I asked on IRC about making the text bigger to help with my low vision issues, several people were patient and helpful.

Adium X is a free program! I highly recommend it to people interested in text chat / instant messaging.

- Ricky Buchanan