When it comes to using the www. in front or your domain, It doesn’t really matter which one you decide should be the forefront of your linking campaigns. However it’s a good idea to make sure that you are consistant with it. As a policy I make sure ALL portions of ANY linking campaign I do promotes the www. version of my site.
I’ve seen a few questions about this and I won’t bother answering the whys. Just know its a good idea. If you are fiding it difficult to find all the sites that link to you with the non www. url you can always search on msn using the
search string. This search string also works in Yahoo and will successfully return a list of all the sites that link to the non www. version of your site.