It's such a shame that you don't get the OST with the game, GCII has fantastic music that really deserves some love and attention. Is there any change of GOG adding the OST to the downloads or is there a rights issue?

First, install XEd from the GCII bonus content. Then, install the GCII Mod SDK from http://www.gamefront.com/files/3679884/Ground_Control_2_Mod_SDK (installation instructions are contained in a readme within the zip file). Open WinSDF.exe, and from within it open gc2data.sdf within the GCII main directory. Scroll down until you find the section with entries from the 'music' folder (first entry is music/adagio_calm.mp3). Highlight all these music entries (left click the first file then shift click the last file to select everything between them) and press 'Extract files'. Now, in your GCII installation folder, you'll now have all the music from the game within the 'music' folder. ( :

Edit: see attachments below for screencaps of winsdf and the extracted files