Drives me nuts that Finder doesn't have a hotkey for file compression. You can use this script triggered with Quicksilver/FastScripts/LaunchBar/Butler/Alfred...

Finder File Compression AppleScript

-- source:	http://hints.macworld.com/article.php?story=2011030403522197
-- from comment Authored by: regulus on Mar 04, '11 09:13:11AM
try
	tell application "Finder"
		set theSelection to the selection
		set selectionCount to count of theSelection
		if selectionCount is greater than 1 then
			error "Please select only one Finder item before running this script."
		else if selectionCount is less than 1 then
			error "Please select one Finder item before running this script."
		else
			set theItem to (item 1 of theSelection) as alias
			set destFolder to (container of theItem) as alias
			set itemName to name of theItem
		end if
	end tell
	
	do shell script ("ditto -c -k --sequesterRsrc --keepParent " & quoted form of POSIX path of theItem & space & quoted form of (POSIX path of destFolder & itemName & ".zip"))
on error theError
	tell me
		activate
		display dialog "Error: " & theError buttons {"OK"} default button 1 with icon stop
	end tell
end try