Simon Wheatley

Allows authors to set their location, and then display it on a Google Map.
Adds a template tag: <code><?php al_list_authors(); ?></code> with the following available arguments:
<ul>
<li>include_protected_posts=1 : Include protected posts when calculating the latest post.</li>
<li>echo=1 : Whether to write the map and listing into the page, or return it (so you can assign the HTML to a variable).</li>
</ul>
The HTML output is fairly heavily classed, for ease of CSS styling, but if you need to adapt it you can. Create a directory in your theme called “view”, and a directory within that one called “author-listings”. Then copy the template files from <code>view/author-location/</code> in the plugin directory into your theme directory and amend as you need. If these files exist in these directories in your theme they will override the ones in the plugin directory. This is good because it means that when you update the plugin you can simply overwrite the old plugin directory as you haven’t changed any files in it. All hail <a href="http://urbangiraffe.com/" rel="nofollow ugc">John Godley</a> for the code which allows this magic to happen.
Plugin initially produced on behalf of <a href="http://www.puffbox.com" rel="nofollow ugc">Puffbox</a>.
Is this plugin lacking a feature you want? I’m happy to accept offers of feature sponsorship: <a href="http://www.simonwheatley.co.uk/contact-me/" rel="nofollow ugc">contact me</a> and we can discuss your ideas.
Any issues: <a href="http://www.simonwheatley.co.uk/contact-me/" rel="nofollow ugc">contact me</a>.

Author Location

Allows authors to set their location, and then display it on a Google Map.

BMLTGuy

This plugin is really meant to be an aid to folks doing data entry, and trying to find locations with Google Maps. 
It shows two forms: One on the left, and one on the right. The left form allows you to enter address information, or a longitude/latitude pair, and the right form shows the result of a geocode lookup or a reverse geocode. 
It is possible to display an interactive map, and also to examine the raw JSON data sent back from the geocode/reverse geocode lookup. 
This is an extension of a utility that was written in order to help data entry personnel enter accurate address information. 
It has administration options (“Geolocator Options”, in “Settings”). 
The plugin outputs highly optimized code that is XHTML 1.0 Strict compliant, as well as WAI AAA.
<h3>Usage</h3>
To use this utility, you simply enter address information into the fields in the left-hand form. You can enter all the information in one line, if you wish. 
The string that is displayed above the entry is what is actually sent to Google Maps to be geocoded. Once you have filled in the address, click on “Address Lookup”. This will send a geocode request to Google Maps. 
The response is parsed, and shown in the right-hand (gray) box. A set of arrow links will appear between the two forms. These allow you to easily transfer results into the entry form. 
If you enter a longitude and latitude value into the bottom two boxes in the entry form, you can do a reverse geocode. This asks Google Maps to figure out an address, based on the values in these boxes. 
In many cases, Google Maps will return more than one response, and you can cycle through these responses. 
Each response shows an “accuracy” number in a scale, above the response. The more accurate (confident) the result, the closer the scale marker will be to the right. 
In the interactive map, there are two markers shown. The yellow one reflects the long/lat pair in the left window, and can be moved around. Clicking in the map will move/create the marker, and fill in the long/lat fields. 
The gray marker reflects the position of the current response, and cannot be moved. 
The raw data window shows the entire response from Google Maps, presented in a hierarchical fashion. If there are more than one placemark, each mark will have a link that will bring that mark into focus in the gray form.

Geolocator WordPress Plugin

This is a plugin that displays a "worksheet" for verifying and researching addresses with Google Maps.

Author Location vs Geolocator WordPress Plugin