WordPress MU

Sorry for my Stupid questions but How to redirect my word.. install

http://www.xxx.com/wordpress to http://www.xxx.com

is possible to use some plugging ? for that,

I know some people will say RTFM

This sounds like WordPress, not WordPress MU, but moving your installation to the server root directory means:
- moving all the files from /wordpress to the root directory
- changing all references to the /wordpress directory in the database to point to the new location

We so need to change those links.

WPMu needs to be installed within the root of where you;re going to serve the blogs from. To place the file into a subdirectory requires a rewrite that will cause other issues with the site as well as load concerns.

And, yes, please read the readme file as I believe this is covered in there.

Install Point 3: If you want subdomain blogs, you must use the root of your site.