There's a nice awk program called vtree (ftp link below) as well. You can get a native Windows gawk binary here. I haven't tested it with Windows because I don't have a Windows machine here at work, but it should work.

ftp://ftp.armory.com/pub/scripts/vtree


Edit: Now that I look at it, I don't think it'll work in Windows without some heavy tweaking. Still, great little awk script to have around for all the unix/linux people out there, it works great.