AppleScript to unlock your Mac's screen. (Use EventScripts to automatically trigger script when a Bluetooth device (e.g., your iPhone) enters your Mac's range: http://www.mousedown.net/mouseware/EventScripts.html)

entering_range.scpt

-- You need to create a Keychain item whose name matches what you use in place
-- of "[keychain_item_name]" on line #7 (and whose password is identical to your
-- user account's password).

tell application "System Events"
	if ((get name of every process) contains "ScreenSaverEngine") then
		set pw to (do shell script "security find-generic-password -l \"[keychain_item_name]\" -w")
		tell application "ScreenSaverEngine" to quit
		delay 0.5
		keystroke pw
		keystroke return
		-- set require password to wake of security preferences to false
	end if
end tell