The migration from msn search to live.com search will occur over the next few days. Microsoft says "The Live Search interface is designed to display a better visual blend of paid and organic results. For example, you'll find complementary fonts, less contrast around ads, and justification of ads with organic results" ..... So watch your CTRs
I'm guessing, that unless you have a high relevancy, the organic search results will outperform your paid ads, at least that's what I hear