configuring N1 with tmo's $10 unlimited web for phone service

hi folks,

I have an unlocked N1 with a preexisting tmo My Fave Five contract (soon to end in 3 months). When i try to go online using 3g I am instructed to purchase the $30 smartphone internet service. Since I will be a light user of the data service it would be more fitting for me to get the $10 unlimited web for phone service.

I would essentially be using the web to post messages on facebook, read news etc. I suppose the heaviest usage would be with the google navigation and eventually VoIP once I learn a little more about it. I don't know if this has already been covered in the forums and I apologize in advance if this is the case. Being a first time smart phone/3G user I'm not sure if I searched the forums using the right parameters.

If someone could point me in the right direction or tell me what settings I need to change I would be most grateful..