How do I keep SSH connections open on MBP? / Running bash script at boot

[JimXugle]

I'm trying to keep an SSH connection on my MacBook Pro open as much as possible so I can use it as a SOCKS proxy and as a cheap way to track my notebook if it were ever to be stolen.

I've got authorized keys set up, so the following script seems to work pretty well.

#!/bin/sh
while true; do
	ssh -R 4000:localhost:22 -D 8575 laptop@dynamicdns.awesome.is -p 4088 >> /dev/null
	sleep 60
done

My Question:
How do I get the script to start running at boot, even before the user logs in?

I'm on OSX 10.5, soon to upgrade to 10.6. A solution that works on both would be ideal.