ICS It still works with Vista, I've used it.
The steps are similar to what Topper has described. (Im not home, so I cant tell you exactly how to do it). As far as I remember you can do it by bridging the connection too.
One thing to remember is to turn on DHCP on the dreambox so that it gets the a correct IP address, gateway etc,
Micr0s0ft use different IP address ranges than what standard DSL equipment does. Your laptop will be acting as a DHCP server if you use ICS (Also as the Gateway and Name Server), so the IP address you have assigned to your dreambox will not work.
Bridging is slightly different however, For simplicity's sake, I would use ICS.