UK: Can I just use the iPhone 3G SIM with a Nokia/other?

I’m looking to ditch my BT broadband connection, maybe not now, but when I can. I don?t use the landline for voice, just broadband, which is looking expensive for the service provided.

The 3G iPhone O2 deal has an unlimited data, but you can?t tether an iPhone. You can tether other 3G phones.

Question ? If I bought a 3G iPhone with unlimited data, popped out the SIM and put it into a phone that supports tether do I get unlimited 3G access for my laptop/PC/home network for the O2 monthly fee?