Does it matter if your sites are accessible by www and without the www in the address like http://www. or just http:// .

I've got links with www and without all over some of my older sites going to the same pages.

If it does matter or if there is even a chance it could cause a duplicate content penalty or lessen my page rank, how could I write a htaccess to add the www to everything? Would this convince Google there is only one page and not two?

I can't speak for Google but since the use or lack of WWW is a server side setting and resolves to the exact same page if lack of is enabled I don't hink it matters.

Worry about your content. With content they will find and list you.

Colbyt

Does anybody know if it matters or not for sure though?

It won't matter which one you use, but you do want to use just one. I prefer to have the www, but that's just my preference.

What you want to do is add a 301 redirect from one to the other. Here's code you can add to your .htaccess file to redirect from non www to www (I think I actually found the code somewhere else in this forum):

Options +FollowSymLinks 
RewriteEngine on 
RewriteCond %{HTTP_HOST} ^yoursite.com [NC] 
RewriteRule ^(.*)$ http://www.yoursite.com/$1 [L,R=301]

If you don't already have an .htaccess file you'll want to add it to the root directory for your site. And you obviously need to replace yoursite.com with your actual domain.

Yep, consistency is important, pick one 301 the other to it

I'm going to use that code, thanks.

I used a 301 on my site too.
otherwise you may have your PR dilluted between the domain and the www. subdomain iif poeple link to both.