GpxUpdate is a Geocache manager that allows you to update co-ordinates for puzzle caches, then export a modified GPX file. From there you may choose to convert to Google Earth format, copy to a GPS, copy to a PDA, etc.
The important thing is that it stores changes to files, rather than the file itself, meaning you can continually update the GPX file from geocaching.com, then apply the changes for the caches you've solved.
It's freely available (both in source code and as an end user program), and can theoretically run on any platform that supports Java and has a port of SWT/JFace. It has been tested on Linux and Mac OS X, and should work on Windows.
You can download GpxUpdate in one of two ways:
Note: You'll need Java 5 or later installed to run GpxUpdate. Mac OS X 10.5 includes Java 5; Windows and Linux users will need to download it though. If you just want to use GpxUpdate, download the Java Runtime Environment (JRE). If you might want to compile or develop for GpxUpdate or another Java based project, download the Java Developers Kit (JDK). The JDK includes the JRE, so you don't need to download both.
Download and install the required software:
In addition, if you wish to develop code for GpxUpdate, you will probably want to download the Eclipse IDE. If you just want to compile from sources, you won't need to download this, however.
After installing the above required software, you need to download the sources using subversion:
$ svn checkout https://gpxupdate.svn.sourceforge.net/svnroot/gpxupdate/trunk gpxupdate-trunk [...] $ cd gpxupdate-trunk $ ant
Packages for each supported platform should now be in the "dist" directory.
If you do make modifications to the source code, please consider sending me a patch with the changes so that I might include it for everyones benefit.