difference between mysite.com and www.mysite.com to google

[darkdmr]

Hello to all. I have a site www.pishtovi.com. I noticed my rank is different
when I go to pishtovi.com and www.pishtovi.com. I have some links from other sites which link to me in both the ways. Is this a loss for me?
I found in the forums the way to rewrite the .htaccess file in this way :

RewriteEngine On
RewriteBase /

# for non ssl
RewriteCond %{HTTP_HOST} !^www\.youdomain\.com
RewriteCond %{SERVER_PORT} ^80
RewriteRule (.*) http://www.yourdomain.com/$1 [R=301,QSA,L]

Is this the only this I should do to get better ranking?

I will appreciade your help.

[RedConvertible6]

I read an answer to this in searcheninenews.com... Its on PDF so I'll just write it here...

basically...
http://pishtovi.com
and
http://www.pishtovi.com

are technically 2 different URLs

If those who link to you use these 2 different URLs to point visitors to your homepage then your PageRank is being diluted by a factor of 2.

Consider also:
http://pishtovi.com/
http://www.pishtovi.com/

I'm not sure if URL re-write would help. Would it be difficult to contact the sites linking to you and have them change the URL's?

[darkdmr]

10x for the answer, I already made it with apache MOD-REWRITE. It won't be difficult to change the incoming links - all them to be www.pishtovi.com.