.pk3 is nothing but an ordinary zip file. You can open it with any Zip Compressor/Decompressor, e.g. Winzip, WinRar, WinAce, PkZip and many more. IF you wann make pk3s just make a Zip-File and change the .zip to .pk3 GL> Apparently WinZip can view what's in a pk3 file, cool!