Microsoft indicated it will switch over its main search engine site to its own back-end system today from Yahoo's, also launching a major media campaign to promote its own search technology. MSN officials said it would be bigger than even the MSN 8 or MSN 9 launches. The MSN 8 launch involved media spending of about $300 million. McCann-Erickson developed the traditional elements and online agency Avenue A/Razorfish ran online media buying. T3 helped with online creative, and - intriguingly - Microsoft hired 42 Entertainment, a viral firm to do some as yet undisclosed project. A ClickZ piece indicated TV creative - also acting as a creative basis for the other media - would involve a pulsating box that morphs into different shapes, eventually becoming the MSN search box, out of which flies the MSN butterfly.