How to make applescript run hidden

How do i make a applescript run hidden and start up on startup. Thanks

tell application "Finder"
	activate
	say "Hello. Welcome to Luke's iBook"
end tell

and also set the computer volume to highest

Create an AppleScript file,

set volume output volume 100

save it as an application,
drop it on Drop Script Backgrounder (http://www.versiontracker.com/dyn/moreinfo/macosx/14932),
and add it to your Login Items list.