As I have mentioned in my other posts, Microsoft Adcenter is not applicable for those based in Asia. You have to go through their assigned reseller in the respective countries. In Asia, they are known as Microsoft Advertising, the going rate to run a campaign on the Messenger, Hotmail, Spaces, Events and MSN pages are available on per impression and per click basis. The last time I was presented with a SG$10k proposal.
Anyway, if you want to learn more about their offerings, do sign up for their Microsoft Advertising newsletter – click here.