There is an easy way to start a program during system boot. Just put this in your crontab:
@reboot /path/to/my/program
The command will be executed on every (re)boot. Crontab can be modified by running
crontab -e
More information about crontab options is available in the man page:
man 5 crontab
[robg adds: I haven't tested this one...]
Mac OS X Hints
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