My Maps Editor is a recent free addition to the Android Market, the result of
20% time from Brian Cornell, a software engineer at Google. The app allows full viewing and editing of the My Maps section of Google Maps, with a few bonuses like GPS support and local caching. With My Maps (you can find this as a tab in google maps), you can add placemarks, shapes, and paths, upload photos, and insert HTML formatted content in the placemark description. You can then share your custom map, keep it private, or open it up to collaboration.
With this application you can create, edit, share, and view personalized maps on your Android powered phone synchronized with the My Maps tab on Google Maps. It supports full editing functionality for markers, lines, and shapes, plus the ability to mark your location using GPS or attach a photo directly from your phone.
Click through to read the rest of the review, and see lots of pretty screenshots.
The app is a 493KB download, and well worth it. All of your map data is stored on your SD card; the actual map tiles still have to load from the cloud, but Google Maps caches a little of that anyways. Since My Maps is a Google service, you have to log in with a "@google.com account" if you are using AppsForYourDomain to host your email like me (buffawhat.com email uses Google FTW).

After a successful login, My Maps Editor will pull any custom maps you have in your account. I actually use My Maps, and have a few already to go. Lets take a look at Shop Local, which is a collection of some of my favorite places to shop and eat in the Elmwod Village area.

The first thing I noticed is that My maps will replace any custom marker icons with defaults. You can look on the web version of My Maps and see that the markers are custom icons that I host on my server. I was a little bummed at first (I love my cutsey icons), but it quickly went away when I saw that the rest of the formatting for the marker info loaded perfectly.

Notice that you have the option to move the marker somewhere else, or edit the information. In the edit screen, you can also change the marker icon to one of the many multicolored symbols and pinpoints that Google Maps has to offer.

Creating a new map is a breeze as well, and probably the strongest use for My Maps Editor. Yesterday, as I went about my recreation duties, I tracked my location with GPS. When we arrived at a POI, I tapped the plus sign and selected "Mark my Location." A new marker showed up where the GPS said I was, bouncing for me to edit it further. In the spirit of Moblogity (new word, mine), I tapped "Add Photo" and took a picture, which was loaded to Picassa and HTML embedded in the marker description.



You can also select from your Picassa Web album, or choose a photo from your phone. When loading from Picassa, thumbnail load times are suprisingly quick on EDGE. Also, note that My Maps Editor creates an album for you called "Drop Box" inside your Picassa account.
Lines and shapes edit and place fairly well, though there isn't any dragging support: you must tap where a point should go. The one super limitation is that you can't get directions from a marker, but I still see this as one of the best map applications to date.
From the Google Mobile Blog