Email Petitions Plugins allows you to easily create petition forms on your site. This plugin was created by Kreg Wallace that was quite good.
When visitors to your site submit the petition form, a copy of your message will be sent to the email address you selected. The petition message will be signed with the contact information provided by the form submitter. After signing the petition, visitors will have the option of sharing your petition page with their followers on Facebook or Twitter.
Signatures are stored in the database and can be easily exported to CSV format for further analysis. You may set a goal for the number of signatures you hope to collect and then watch as a progress bar tracks your petition’s advance toward it’s goal. Petitions may also be configured to stop accepting new signatures on a specified date.
SampleRead the petition