I checked the download link on all language versions (DE, EN, ES, FR, CZ) and on all pages it was an APK file.
Did you use this link: http://downloads.rungps.net/Run_GPS_Trainer_UV.apk ?
Obviously your browser interprets the content of the file (an APK file actually IS a ZIP file, see http://en.wikipedia.org/wiki/APK_(file_format)) and changes the suffix. Probably it's enough to change the suffix to ".apk". If that does not help, I can send you the file by email (but it's very large).
Which browser do you use? Maybe the problem is caused by a virus scanner trying to detect threads in downloaded archive files.
The ZIP file is only for Windows Mobile. You have to download the APK installation file.
Step-by-step:
1) Download the APK installer from http://www.rungps.net >> Downloads
2) Copy it to your SD card (connect USB cable, then mount the SD card from the Android status bar)
3) You need to have a tool that allows you to install software from external sources - we recommend "Astro File Manager" (free), which you can get from Android Market
4) Using Astro, browse and install the APK file
Has anyone tired to install Run.GPS on a Android 2 mobile phone? I have a Motorola Milestone and purchased Run.GPS. I downloaded the software as a .ZIP package. I can put the file of the zip package on the micro-sd card in the mobile phone, but I do not know where to copy those. Any hints?