Felix Triller

This plugin replaces coordinates, i.e. latitudes and longitues, between a [coord]-Tag with a link to Google’s map service.
Example:
[coord]49.579276566362985,10.9292078018188488[/coord] comes up as <a href="http://maps.google.de/maps?ll=49.579276566362985,10.929207801818848&q=49.579276566362985,10.9292078018188488&t=kbd&z=15" title="Google Maps" rel="nofollow ugc">(49.5792, 10.9292)</a> 
To adjust the link layout of transformed links open wpCoordinates.php in your favorite editor and adjust the following variables:
<ul>
<li><code>$zoom</code>: the zoom level, default is 15. Try some values between 1 and 17 (I guess)</li>
<li><code>$type</code>: map type, i.e. m for map, k for a satellite image, h for hybride (satellite image with street names, etc.), p for terrain</li>
<li><code>$url</code>: URL scheme, replace .de with .com for an english version of Google Maps. DON’T forget %LAT% and %LONG%</li>
</ul>

wpCoordinates

wpCoordinates replaces coordinates between a [coord] tag with a link to Google Maps.

Gouel provides an interface to create maps. You can create trips with a list of points and a route (line). You can link points with your posts.
Gouel works with the multilingual plugin WPML. You only have to create the map once, for the principal translation. The map will appear for all the other translation.
<h3>Known Issues</h3>
Using the Opera browser, the routes don’t show (the markers do, though).
<h3>Future Improvements</h3>
<ol>
<li>custom icons for markers</li>
<li>shortcodes</li>
<li>auto-localization on add/update post</li>
<li>wysiwyg editor for marker description</li>
<li>templates for description</li>
<li>variables for description and title (such as post adress, post title, latitude, longitude, …</li>
</ol>

Gouel

Gouel provides an interface to create maps linked with your posts.

wpCoordinates vs Gouel