Google ranking and www vs non-www,

Hello, new member here.

Here's my issue:
I have a site that's setup where it defaults to http://mysite.com even if you type in http://www.mysite.com in the address bar.

BUT, I've been messing with google webmaster tools and discovered that nearly ALL of my incoming links point to the http://WWW.mysite.com.

First, is this a problem with ranking?

Second, can I edit the HTACCESS file without creating a nightmare?

One other note, I've attempted to create an XML sitemap (from xml-sitemaps.com) for the http://WWW.mysite.com but it couldn't find the URL.
I have, however created one for mysite.com without a problem.

Much thanks in advance.

I suggest you use http://www.mysite.com

XML sitemap,why don't created it yourself..

Well.....I do not thonk it does effect on rankings.......and you can create XML sitemap yourself by following amy other XML sitemap if sitmap.xml gives you error........