To say that Deniska's GPS/Mapviewer for the PSP is a hit is an understatement. More like a big, big, big hit. It also generated a lot of questions from PSP users on how to use this homebrew app. The talented and generous Deniska issued this tutorial to help all you directionally-challenged people from getting lost:

The map viewer package includes the cygwin script (in the scripts) to get the maps for any given GPS coordinate:
./getmap.sh [latitude] [longitude] [base zoom] [size]

• The script takes 4 arguments. You can find out the latitude/longitude of the area you want by using following tool: http://www.mapki.com/wiki/Get_Lon_Lat
• Base zoom [0-16] corresponds to the values of the zoom bar on that tools map (0 being the most detailed map)
• Size is the number of the maps 256 pixel segments. Size 16 will create a base map 4096x4096 pixels. Displaying maps, large than 4096x4096 will suck up all the PSP's browser memory.
  

• Create a folder /WEB in the root of your PSP's memory stick
• Download a small map of center of Paris from: http://deniska.dcemu.co.uk/bin/_PARI....34497_16x.zip (paste the link in to your browser if it does not work directly)
  
• Unzip the map into to the WEB folder
• The WEB folder should have 1x, 2x, 4x... folders in it, as well as 1x.html 2x.html...8x.html files...
• Open PSP's web browser and type in following URL: file:/WEB/8x.html

• Click on the map to zoom in or use LEFT TRIGGER to go back & zoom out. Use directional buttons to move up/down/left/right on the map.