ponyboy96 - 12:02 am on Aug 25, 2011 (gmt 0)
A couple things come to mind and are usually the case. Don't immediately assume a penalty. Check these things first:
Double check your robots.txt and sure you aren't blocking them
Check the settings for WP, make sure you didn't accidentally check the box to make the site invisible to search engines.
Check your server settings to make sure you aren't blocking the bots in some way.
Other than that, I would need a little more info,
Did you change domains? IPs? Domain registration?
Did you make any recent changes to the site? URL changes?
Have you been building links?
How many visits do you normally get from Google?