A note for anyone who is Googling to see if the OS X 10.5.7 update fixes keyboard mapping problems introduced with 10.5.6 and non-US QWERTY keyboards, including using the System Events keystroke command, or various weirdnesses involving Microsoft Office:

Yes, Virginia, 10.5.7 is once again safe for your Dvorak keyboard and AppleScript macros.

tell application "TextEdit" to activate

tell application "System Events"
	tell process "TextEdit"
		keystroke "testing"
	end tell
end tell

--10.5.6: y.oycbi
--10.5.7: testing