Ha! On my Leopard setup, I open up Terminal and type tab, tab and then I get asked: "Display all 1475 possibilities? (y or n)".
So I think it's better to learn them on an as needed basis.
on adding folder items to this_folder after receiving these_items
tell application "Finder"
if not (exists folder "Done" of this_folder) then
make new folder at this_folder with properties {name:"Done"}
end if
set the destination_folder to folder "Done" of this_folder as alias
set the destination_directory to POSIX path of the destination_folder
end tell
repeat with i from 1 to number of items in these_items
set this_item to item i of these_items
set the item_info to info for this_item
if this_item is not the destination_folder and the name extension of the item_info is not in {"zip", "sit"} then
set the item_path to the quoted form of the POSIX path of this_item
set the destination_path to the quoted form of (destination_directory & (name of the item_info) & ".zip")
do shell script ("/usr/bin/ditto -c -k -rsrc --keepParent " & item_path & " " & destination_path)
end if
end repeat
end adding folder items to