I'm trying to start a service that depends on networking being started, whenever the computer is rebooted. I have a few questions:

1. Is this easily possible from an /etc/init.d script? I have tried creating a script here (conforming to the standards), but I'm really doubtful that it's even running on boot, let alone working. When I test it manually, it works.
2. I've seen the new Upstart service, but as far as how that actually works, I'm completely in the dark.

How can I make a script that runs on boot which runs after networking has been started? If I could run it after connected to wireless network, even better :)