Got this email from Nokia earlier today. Don't know if this applies to the N900. As no one else here seems to have received it I am guessing possibly not. I may just have received it because of the three days I had an N97 before I realised it was the biggest peace of thrash ever. Remains to be seen what exactly this means. Is it just yahoo contacts you will be able to chat to or will it also apply to msn contacts for example. Hope so even though the email does not suggest so.

You have received this message because you have used instant messaging (IM) from the Contacts application on your Nokia phone. We are announcing changes that require your action to continue using this service.
Nokia recently announced an alliance with Yahoo! in which Yahoo! will begin powering Ovi Chat. This alliance will bring exciting new functionality to Ovi Chat in the coming months, including the ability to add Yahoo! Messenger friends to your Ovi Chat friend list and access Ovi Chat from a browser.

To prepare for these changes, you need to begin using the Chat application on your Nokia phone. Access the Chat application from the Chat icon on your Nokia phone or by downloading it from the Ovi Store (see links below). Then, launch Chat on your phone, select Register/Create Account, and follow the instructions to log in with your existing Ovi account credentials.
If you are viewing this email on a computer, click here:>> http://ct.nokia.com?105803688&121-EISKI to send the Chat application to your mobile.If you are viewing this email on your mobile, click here:>> http://ct.nokia.com?105803688&121-EISKL to download the Chat application.
The Ovi Contacts application will continue to be supported by Nokia, but you can only take advantage of the new Ovi Chat capabilities or chat with other Ovi Chat users if you are using the Chat application. The Chat application also gives you access to other popular IM services so you can chat with your friends across multiple portals/communities from the same place on your phone.
We look forward to seeing you on the new and improved Ovi Chat Powered by Yahoo! service.Sincerely,Ovi by Nokia