Quick correction:
And if I must have MSN messages, I can pull my Orange SPV out; it logs onto that quite effectively. No, it can't talk to anything else - that's Not The Microsoft Way.
 
Wrong, wrong and wrong. It's the Microsoft Software way. Solution - use someone else's software. Agile Messenger 2.0 ( http://www.agilemobile.com/agile_messenger.html ) works with Microsoft Smartphones such as the Orange SPV, and lets you connect to MSN, AOL, Yahoo and ICQ.

It's also free, works well and doesn't give you pop-ups, at least as far as I've seen.