Use IdeaScale or BubbleIdeas or SalesForce instead.
Ideally for Gov 2.0 scenario you'd want to deploy tools that handle duplication, user identity and even curse in an automated sort of way. And the top-most-voted idea may not be the best strategic decision either.
GetSatisfaction & Uservoice are good for small scale stuff which orignally have been developed for consumer feedback.
Adam J. Wright