My Site Migration

1) Log in to appropriate My Site host farm

2) Open a command line and navigate to C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN.

3) Backup the site:
Stsadm.exe –o backup –url http://my/sites/-filename e:\newalias.dat

4) Delete the site:
Stsadm.exe –o deletesite –url http://my/sites/

5) Restore site with new name:
Stsadm.exe –o restore –url http://my/sites/-filename e:\newalias.dat

6) Migrate old account to new:
Stsadm.exe –o migrateuser –oldlogin domain\oldalias –newlogin domain\newalias –ignoresidhistory

7) Update existing user profile at: http://enterprisessp/ssp/admin/_layouts/ProfMngr.aspx?ConsoleView=Active (or regional SSP as needed where the account is located. Be sure to update the Personal site attribute and the PersonalSiteURL attribute if they exist.

Now the work is done, send an email to the user to load their new site at http://my/sites/. If/when prompted, they must agree to set the new site as their default My Site.

Credit: Sharepoint Forum