The paper gives an overview of the situation, and offers some guidelines on what the transition will entail, including some special considerations for Director developers. It also mentions the official position from some of the main Xtra developers on their plans to convert their Xtras.
Should you require additional information, please feel free to contact me.
Here is a direct link to the PDF document (317 KB
http://www.inm.com/about/newsroom/whitepaper/intel-mac-whitepaper.pdf