Well, after less than a year since I wrote the Web2Messenger (W2M) PHP API, it looks as though it has finally died.
When I was using the system for my dissertation and also writing the API, I did notice a lack of support and now finally it ha totally gone.
The forums return an SQL error and all the bots are offline which means all is sleepy in the W2M world.
It it sad to see such a service to but no worries, Microsoft have released some code for Windows Live Messenger to integrate into PHP.
Check it out over at CodePlex.