hct, you'll want to look at a couple commands...one is ls -l ( <- that's a lower case L ) ;-)
Also, you'll want the du command.
du -ks . ( gives size of directory and it's contents )
du -ks * ( gives size of files and of directories ).
As for quota...is there really a reason, any more, to have a quota system? In this day and age of personal set-top servers with 100s of gigs of HD space for pennies a gig? If so, I'd check out man quota, and then do a google search for "howto quota", as I don't recall off the top of my head as to how to set it up.