Hi everyone,
If you go to Google and put "link:[insert domain name]", it brings you back a list of all the sites linking to you and at the top top right of the page gives you a total.
It's not completely accurate. Often it will list other pages within your URL as additional websites etc, but it gives you a good indication.
So, just incase my instructions aren't totally clear, if you wanted to see how many link to
www.t-shirtforums.com, you would enter into the search field:
link:
www.t-shirtforums.com
Hope that helps!