I mounted my box.net account successfully with the following line:
I added my username and password to the davfs2/secrets file
and I now mount box.net automatically with the following line in fstab:
http://www.box.net/dav /media/box.net davfs

But I now realize that I can't write files to my box.net folders without being root.

And when I tried copying files to this volume (as root) I got this error message:
What I would like to do is make my "localhost" directory redirect to the box.net volume, so I can edit my web site from my office and from home, but I doubt this is possible. Thanks for the help.

You can try adding the umask=007,gid=46 options to the line in fstab. Make sure you are a member of the plugdev group (gid=46) but you should be if you can use optical drives and jump/flash drives.