Possible Duplicate:
Could I buy a domain name to increase traffic to my site like this?

I have a website with multiple keyword based domains ( 2 actully) Now both domains are common google searches for the topic. What i'm intrested is to handle the domains as such that google can recognize the seconed domain with the same page rank as the primary domain, so it will also appear on the first page. My question is how do i do it correctly so i will help SEO? meaning i want the 2nd domain to be on the first page, because the primary is on the first page for it's keyword.

• do i simple put a redirect in the index.php file?
• Or to do a 301 redirect?
• or change the .htaccess file?
• Or create a domain pointer in the Control panel?