Of course it depends a bit on what your site is all about or what you are offering, but you could also write articles, press releases or how-to guides (on your chosen topic) that you submit at the various directories online, which of course link back to your site and offers.
You could also use sites such as BlogTalkRadio.com to host your own online radio show which is also syndicated on other sites.
Hope these quick ideas help a little.
Xavier