How to delete a MOSS My Site
Deleting a user's My Site sounds like it should be very easy to find, but in some ways it is hidden in the administration and management of MOSS. In order to delete another user's My Site you need to be an administrator in the Site Collection that the My Site resides under.
1. Navigate to your Central Administration site.
2. On the left navigation click on your Shared Services Administration site link. This will be whatever name you chose as the site name when it was first created, ours is called SharedServices.
3. On your SSP Home Page under User Profiles and My Sites click: User Profiles and Properties.
4. In User Profiles and Properties click View User Profiles
5. You should see a list of user profiles. Navigate to the appropriate user and enable the context drop down list. Click Manage Personal Site.
6. If you have permissions you should see the familiar Site Settings screen available in all SharePoint sites. Here you can choose to "Delete this site" from the Site Administration menu.
This is a useful and faster method than manually typing in the URL for each My Site you wish to delete via the browser. You can still choose this method by going to the following URL if you wish to navigate directly to each user's My Site Site Settings page: http://<my_site_web_application>/personal/<username>/_layouts/settings.aspx
I hope this helps
-Ryan