Site is getting hacked again and again

These are the suggested resources for hacked sites – you need to go through all of them to be sure it’s completely cleaned up and you’ve closed any ways the hackers are getting in. You should also talk to your hosting company in case they have a problem on the server:

http://codex.wordpress.org/FAQ_My_site_was_hacked
http://wordpress.org/support/topic/268083#post-1065779
http://smackdown.blogsblogsblogs.com/2008/06/24/how-to-completely-clean-your-hacked-wordpress-installation/
http://ottopress.com/2009/hacked-wordpress-backdoors/

Additional Resources:
http://sitecheck.sucuri.net/scanner/
http://www.unmaskparasites.com/
http://blog.sucuri.net/2012/03/wordpress-understanding-its-true-vulnerability.html