[Novices] permissions & sharing between users

[Steve Petersen]

Hey folks,

I know this should be easy, but I just can't seem to work out 
permissions, or find the information I need on the web or in my books.

Basically, I have a computer at the office with a set domain name and 
sftp enabled (but no web serving or anything).  I'd like users I've set 
up to be able to log in and download / upload files from / to a "public" 
directory of some kind.  First, how would I make a directory like that, 
and where's the standard place to put it?  /usr/share or something?

Second, suppose I wanted a subdirectory of my home directory to be 
shareable in this way.  I tried 'chmod 1777' and the like but still 
other users can't see it, I guess because the parent directory is still 700?

Thanks for any help!
Steve