Sweezely - 2:19 pm on Jan 18, 2007 (gmt 0) Info here. [advertising.microsoft.com]
It looks like the only places your ads will appear are on MSN sites like Encarta (didn't even realise that still existed!) or MSN Travel. Also, it's US only, meaning the literally 7 people who use Adcentre in the UK can all breathe a sigh of relief.
Info here. [advertising.microsoft.com]