Check out this short article, test it and let me know your findings!

http://blog.verticalresponse.com/verticalresponse_blog/2010/05/use-buttons-instead-of-links-and-increase-your-clicks.html

After years of working in the field of usability I found it greatly depends on the seriousity of the site. While great designed buttons tend to generate more clicks, text links are more trustworthy, especially on sites with adverts.