.htaccess help

This may be one for Aqua or another techie wizzard.

I am trying to set up a .htaccess file for my site.

I want visitors who enter my site at http://mysite.co.uk to be redirected to http://www.mysite.co.uk.

Plus any page to be redirected to the same page at http://www.mysite.co.uk

I have tried a couple of things but they have returned 404 not found messages, this will do as I can use a custom 404 page to direct to the index page, but I would prefer it if the user is redirected to the page they are after, but I am concerned that allowing spiders and users to use both http://mysite.co.uk and http://www.mysite.co.uk may cause a search engine to thing they are duplicates.

Any help would be much appreciated, I think the answer may lie in a 301 redirect, but am not sure.

Thanks

Ok.

I have done it. My solution if anyone else wants it is:

Options +FollowSymlinks
RewriteEngine on
RewriteCond %{HTTP_HOST} !^www\.mysite\.co.uk
RewriteRule ^(.*)$ http://mysite.co.uk/$1 [R=permanent,L]