I have installed wpmu to create blogs as sub directories i.e of the format
http://domain.com/blogname
Now I want to convert it into Subdomains i.e http://blogname.domain.com
without reinstalling.I have less than 10 blogs installed.
Any suggestions would be appreciated.
Covered here, just in reverse:
http://mu.wordpress.org/forums/topic/14134
Also open up the wp-config.php file and change the VHOST setting. (Yes for subdomains, no for subdirectories.) Save and then open up the file again to see if the editing has been saved. On many platforms, a file created by the webserver is owned by the webserver and an user may ne be able to edit it. If that does happen, you need to get the root user to change ownership for the file. (ie Contact your host.)
And if you want to keep those blogs, you have to go change the URLs in the db.