Asia_Expat - 12:28 pm on May 4, 2008 (gmt 0)

IMO you should do absolutely nothing until the time comes to make the move. Plan carefully and when the auspicious day arrives, move seamlessly in a straight line to the new domain at the flick of a switch... and be prepared for a dance that will last months... but the dance won't be too bad if you do it properly and retain the old domain with the universal 301 in place permanently.

This was my experience when I moved domains a couple of years ago. Be sure your client is moving for the right reasons though. In my case, it was because I rebranded and retained a .com and wanted to move away from .info.

BTW this thread should be in 'General Search Engine Marketing'...
Yahoo took AT LEAST a year to recognise all of the new page URL's.

[edited by: Asia_Expat at 1:06 pm (utc) on May 4, 2008]