The GMap extension lets you embed an arbitrary amount of fully interactive Google Maps objects into your wikipages. The mapcontrols appear when you move the mouse over the map, and disappear when you leave it.
You can define markers (with bubbles containing wiki-markup) and colored lines with an easy syntax directly in your wikipages (thus making use of the wiki revisioning system).
Two helper modes are available, outputting either current map view settings or coordinates on click, making it easy to choose a map locaton to display and to create markers and lines.
Instalation is easy (just one PHP file), browser compatibility includes Konqueror, Firefox and IE6.
See also User:Mafs/GoogleMapExtension.