Mobipocket is a popular ebook format used in conjunction with paperless geocaching. Mobipocket.com has ebook applications for numerous pda platforms, including Palm, PocketPC, Blackberry, and numerous other smartphones.
One of the reasons for the wide popularity of the Mobipocket format was that until August, 2007, geocaching.com could automatically generate .mobi ebooks and provided the option to include them with a user's pocket query. Since then, a number of solutions have sprung up allowing geocachers to generate their own ebooks from a gpx file.
Tools for generating Mobipocket ebooks
Procedure for using GPX2HTML to generate a .mobi ebook: (Instructions are for Windows)
1) Download and Install the MobiPocket Creator from http://www.mobipocket.com/en/DownloadSoft/ProductDetailsCreator.asp
2) Download GPX2HTML (thanks to FizzyMagic) at http://www.fizzymagic.net/Geocaching/gpx2html/gpx2html.exe
3) Obtain your ######.GPX file from geocaching.com in your email, or generate it from another source such as GSAK)
4) Create a folder on your desktop, name it "Caching" (or anything you like at this point) and copy the ######.GPX file and gpx2html.exe into the folder. Double-click on the folder and then double-click on gpx2html.exe. A DOS box will appear with your caches being displayed as it processes. When it's done, the DOS CMD window will automatically close itself. Takes seconds for a GPX file of say 100 caches.
5) Open Mobipocket Creator Home Edition, create a new Blank Publication, give it a name, double-click on the "Caching" folder, then double-click on the "HTML" folder, highlight all the index.html related files (they are all near each other) and drag them into the Mobipocket Creator programs "Publication Files" window and drop them there. Then back in the Windows Explorer window, click on Edit, then click "Invert Selection" and then drag and drop the rest of the files into Mobipocket Creator.
6) Click Build, your ebook will be built for you and placed in your Mobipocket Reader program.
7) Delete the "Caching" folder, or at least empty out caches.loc and HTML folder, and the original gc.com GPX file in there if you have another GPX file to process.
8) If you have a blackberry, start Blackberry Desktop Manager, plug in your Blackberry, and Mobipocket reader will copy your new publication to your Blackberry. If you are using a different PDA, you need to follow a similar procedure to copy your ebook to your PDA
GPSBabel can be used to convert a .gpx file into a single html file. This HTML file can then be loaded into Mobipocket reader and transfered to your PDA as an ebook.