Finally got around to adding a radial email address finder to my Mappy Email Signup app. Mappy Email lets visitors/fans select their locations on a map and save their email addresses. So you can contact them only when you're in the area (which is more polite). It's basically an open source Eventful.com that doesn't hang all your contacts up in a third party.
The new version finally has a page (/admin/) where you can specify a radius (in kilometers), click the map and see all the email addresses that are within that area. So you can paste them into whatever mailing list app you're using.