tell application "OmniFocus"
	tell front document
		set oTask to (make new inbox task with properties {name:"test", note:"test 2", flagged:true})
		set strID to id of oTask
	end tell
end tell

-- OR
tell application "OmniFocus"
	tell front document
		tell (make new inbox task with properties {name:"test", note:"test 2", flagged:true})
			set strID to id
		end tell
	end tell
end tell