A collection of scripts, I have created. They normally are usefull to me, and possibly can be usefill for somone else.
With this script elevation data can be added to a gpx file. To do so, go to http://www.gpsvisualizer.com/elevation and create a gpx file with elevation data from your gpx file w/o elevation data. Then call this script with both filenames as arguments. The gpx file with elevation data will be written to stdout.