Apart from downloading Prune, there are other pieces of software you may need to install if you haven't got them already. The only one you need to have in order for Prune to work is the Java Runtime, all the others are optional, but you may want to get them in order to get access to some of Prune's functionality.
The only required software is a java runtime, also known as a JRE (Java runtime environment). To run Prune you need to get a java runtime of at least version 1.5, but versions 1.6 and 1.7 also work fine. If you haven't got a java runtime already then it's best to get the latest version available to make sure all the security fixes have been applied.
To install on Linux, simply get it from your package manager. For example, in Mandriva there are several java implementations available (including really free ones), the Sun package is called "java-1.6.0-sun - Java Runtime Environment". Simply select it and it will get downloaded and installed for you. For Debian, do the same with "sun-java6-jre". In Ubuntu it's now easier to install the OpenJDK rather than Sun's one, although you can still install Sun's one if you want.
For Windows, go to the Java SE download page, select the latest version of the JRE (at the time of writing this is given as "Java SE Runtime Environment (JRE) 6 Update 19"), and download the item marked "Windows Offline Installation". Run this executable and go through the wizard installation process. Also see the installation instructions.
Mac OSX users don't have to do anything because "Mac OS X includes the full version of J2SE 1.5" (according to apple.com).
The java3d libraries are used for the real-time 3d display in Prune. To install them, go to java3d.dev.java.net and select the zip file for your platform. Follow the instructions inside, or just unpack the contents of the j3d-jre.zip file into your java installation. If you have Debian or Ubuntu you can get the libjava3d-java package from the repositories (universe for Ubuntu, testing for Debian).
Again, Mac OSX users don't have to do anything here because apparently it is installed already by default. You can check this using the "About" page in Prune.
Note that these java3d libraries are optional for running Prune, but if you want to build the complete source, you'll need to have the java3d libraries installed so that you can build everything.
Exiftool is a multi-purpose tool for handling the exif data inside jpeg files. Prune uses it to save the coordinates into the Jpeg files after correlation. If you haven't got Exiftool you can still read the coordinates from Jpegs and still generate Kmz files containing the photos in the right place but Prune won't be able to save those coordinates in the Jpeg files.
To install on Linux, use your package manager. For example, on Mandriva just type urpmi exiftool, for Debian or Ubuntu aptitude install libimage-exiftool-perl.
To install on Windows, go to sno.phy.queensu.ca/~phil/exiftool and select the appropriate download file. You'll probably want the executable version which doesn't assume that you've already got perl. Open this file with an unzip tool and extract the single file called exiftool(k).exe. Now you need to rename this file exiftool.exe and either move it to somewhere within the system path or extend the system path to include the directory where you saved this exe. See the install instructions for more details.
To install on Mac, again go to sno.phy.queensu.ca/~phil/exiftool and download the Mac package, then install this in the usual way. Or you could use macports (the command is port install p5-image-exiftool I think) or Fink (apt-get install image-exiftool-pm I think).
Gpsbabel is a command-line tool for converting between data formats. Prune uses it to load data directly from GPS receivers, and also to send data back to the GPS receivers. If you don't have gpsbabel installed then these functions won't be available.
To install on Linux, use your package manager. For example, on Mandriva just type urpmi gpsbabel, for Debian or Ubuntu aptitude install gpsbabel.
To install on Windows, go to gpsbabel.org and select the zip file from the download page. Save this file and open it in a zip utility, then extract the file gpsbabel.exe and save it somewhere in your system path (eg the windows directory).
To install on Mac, again go to gpsbabel.org and select the dmg file for Mac. This should be installed in the usual way. Or you can get it from macports (the command is port install gpsbabel I think) or Fink (apt-get install gpsbabel I think).
Gnuplot is a powerful charting tool which Prune uses to draw the charts of altitudes, times, speeds, distances and so on. If you don't have gnuplot installed then Prune won't be able to generate these charts.
To install on Linux, use your package manager. For example, on Mandriva just type urpmi gnuplot, for Debian or Ubuntu aptitude install gnuplot.
To install on Windows, go to gnuplot.info and select the appropriate zip file from the binary download page. Open this file in a zip utility, then follow the installation instructions inside the zip. Also you'll need to inform Prune where to find the executable (now called pgnuplot.exe), using the menu function Settings -> Set program paths.
For the Mac, there is no binary on sourceforge but you can use either macports (the command is port install gnuplot I think) or Fink (apt-get install gnuplot I think).
Povray is a rendering program for generating high-quality rendering of 3d images using the Pov files created by Prune (using the menu command File -> Export POV).
To install on Linux, use your package manager. For example, on Mandriva just type urpmi povray, for Debian aptitude install povray.
To install on Windows, go to povray.org and select your download (32-bit or 64-bit) from the download page. Save this executable file, run it, and follow the installation wizard.
To install on Mac, you can use the povray download page to get the Mac version and install it as usual. Or you can get it from macports (the command is port install povray I think) or Fink (apt-get install povray I think).