Searching for posts by location/postcode/zipcode?

Hi All. I’m building a review site for someone, and while not essential it’d be good to be able to search posts by their proximity to a location – i.e. postcode search (that’s zipcode for all you folks in the USA) > show me all posts (reviews) within 10/15/20 miles of location X etc.

Now, I’ve seen lots of plugings that will let me geotag a WordPress post, but I’ve not seen any with the ability to then search for posts that have been geotagged to a certain city / region etc, and see the localised posts on a map?

If anyone’s had any experience with this sort of stuff I’d love to hear how you implemented it. Thanks everyone!

Rich