Please review this link http://support.google.com/webmasters/bin/answer.py?hl=en&answer=163634&ctx=cb&src=cb&cbid=elq3fvt39ebd&cbrank=0
When you have cleaned out the site you can request the reconsideration there. You will have to signup for Google webmaster tools (which is free) and add your site. This helps verify to google that you are a legitimate webmaster and not a robot.