There are several tools to check back links like: google webmaster tool, google analytic, backlinkwatch and open site explorer etc..
When starting a link building campaign (or continuing one), you want to be able to check your progress and see if you are indeed building any backlinks to your site. You want to be able to see if any of the links are “nofollowâ€, what anchor text is being used for the links, and what quality of site the links are on. Since I have gotten into link building, I have been steadily compiling a list of sites that allow you to check your backlinks. You may have heard of searching Google with “link: yourwebsite.com.†While this does work, it discourages many new (and even some experienced) webmasters because Google doesn’t include all of the links they have listed to your site. Sometimes, they don’t show any. Move beyond using this tool, and try out some of the websites below. .......................................................
This is the fact that backlinks is most important factor when search engines ranking sites, search engines rank well those web pages which have good no.of number of quality backlinks.I think you can use Google Webmaster Tools or backlink watch.