We have the answer in the SEO FAQ's thread but I will post it once again here as well.

I just changed my domain name. How can I switch without losing my rankings?
Code:
 RewriteEngine On
 RewriteCond %{HTTP_HOST} ^(www\.)?old-domain\.com$ [NC]
 RewriteRule ^(.*)$ http://www.new-domain.com/$1 [R=301,L]
I hope it helps.

Also regarding links new user with post counts less than 10 are not allowed to links to keep the spammers away and I hope you will understand this.