I bought a Samsung Galaxy Tab some weeks ago :) but I haven't adquired a 3G plan. This prevents me to use Google Maps and use my device build in GPS capabilities. After some research I found in android market an application called rmap that simply rocks!. You can create your own maps upload them and enjoy.
The problem is, where to obtain this maps? Well there's a desktop application (written in java of course :) ), that creates a multilayer map based in a great huge variety of map engines like google maps (my favorite), bing, yahoo, etc., and can export portions of the map to many diferent file types.
The big problem (not that big) is that rmaps uses an output map format called "BigPlanet SQLLite" that is not supported by default in Atlas Creator. This can be fixed quickly following the next steps in Ubuntu 10.10:
1. Download Atlas Creator from http://mobac.dnsalias.org/ (I'm using version 1.7 but the latest stable version is 1.8, desicion up to you)
2. Download SqlLite Libs from http://www.datafilehost.com/download-909a5d21.html. (I used ubuntu 9.10 x64 but this is dependant of your cpu)
3. Download SqlLite.jar from http://www.ch-werner.de/javasqlite/javasqlite-20100727-win32.zip (yes! is a windows build but don't worry remember that java is multiplatform)
4. Copy libsqlite_jni.so and sqlite.jar to 3-Mobile Atlas Creator 1.7 folder. (In the same place that you can fin start.sh)
5. Run Mobile_Atlas_Creator.jar (java -jar Mobile_Atlas_Creator.jar)
Now you can select the area that you expect to use offline (for example your entire city or your next vacation destiny) and select the zoom level that you want to be available. (WARNING selecting level 18 and 19 will produce big map databases, personally I use from zoom 1 to 17). Finally, don't forget to select "BigPlanet SQLLite" format, name your atlas and sections and run "Create Atlas".
After some minutes depending in the area selected you will have a map file in /home/atlases/ that you need to copy to your android mobile device in the path /rmaps/maps/.
This way you will have a Google Map (or any provider map) completly offline and functional!