Starting client at boot

I want the client (and eventually server too) to startup on my monitored
machines at bootup. Now I can get the process up and running through
init.d as user root but not as hobbit. Whats the simplest way to do:

 
su hobbit

/usr/local/hobbit/client/runclient.sh -hostname=xxx

 
At machine boot?

 
Im new to this area of Linux so it's probably very simple and im missing
something!

 
Craig