[Voxel]

i'm using winzip. pk3 is basically zip. i'm sure you can do it all in other programs easier but here's a quick way that works for me...
clone a small pk3, rename it to your liking, open it with winzip, delete all the files inside, have a directory for the map setup with all the sub dirs in order... then in windoze explorer highlight all the folders you wanna toss in and drag & drop them in the empty pk3. boing! done.

grab 1 of mine and see how i did it if you're still confused. i'm no expert, but seems to work ok. http://www.viziongrafx.com/vg