WordPress MU

hi,
A few of my users have their own themes. how i can add thses themes so that only these users who owns these themes,can see and use them? I mean if user A has created a theme, then I install it and only user A can use it.

Ftp the theme on to the server.
By default it will be disabled for everyone.
Do not go to the Site Admin themes menu.
Go to Site Admin -> Blogs. Find that user's blog.
Click "Edit".
On the right there's a column that says User's Themes. There will be a list of disabled themes with a checkbox beside each one.
Tick the one that you know is theirs.
Scroll down and click the "Update options" button.

That blog now has that theme enabled just for it.

thanks a lot. I went there. there is no usar's theme column. but template and stylesheet. but I think it is the answer. Thanks again.

Yes that is the way you do it. What you need to do is move your mouse to the right of the screen and then the screen will scroll so you can see that menu. Im not sure why there is no scroll bar for that area, it is actually kind of hard to move around in the settings that way. Be sure to update settings before you leave to. I did notice however, if you use firefox for your browser instead of IE then you can see the menu and scroll.