Using my recently acquired G1 (it's gonna be real tough to give this one back) I went to seek out, download, and install the new application. I'll go through the steps as if you've never used or seen a G1:

Using the Android Market application that comes installed in the home apps, I used the search utility as a starting point. Searching for terms like "google maps" "google maps editor" etc.. I couldn't actually locate it! I believe I eventually found it searching for "maps editor"... go figure! I then downloaded the free application and installed on the device... this was very fast and took about a minute in total.

I then found the Google MyMap Editor app on the G1 application home area. Calling up the app, I immediately make a connection to my google account - note: when you first fire up your G1 it requires you to connect and setup a service between the device and your Google account.

Then, using the MyMaps Editor application I am presented with a list of all of my existing custom MyMaps... sure enough, all the maps I've made to date are available for viewing. Optionally, I can create a new map. I selected that option and then added a place marker for my current location; this is done via the device's integrated GPS. So far, that's all I've done to my map, howoever, options are also there for adding a point, line or shape - apparently, one can also add a photo to the map but I haven't figured that step out yet! Unfortunately I couldn't even get my position placed on the map as the device was not able to grab a GPS fix on my position... perhaps because I'm inside (this is no problem with my Nokia N95). As a second effort I even went out onto my deck and held up the device (reminiscent of Robin Williams in RV!) but still no go... plus, it's currently about -10 degrees here in NOCO so I'm giving up on that one.

The Google MyMaps Editor App installed in G1 

Using the MyMaps editor on G1 to get a fix on my location using GPS 

My new MyMap is saved in my Google Account preferences and available via mobile or PC client