1. Damn right I do! Saves me lots of dough, especially if you sit just out of range of wi-fi at a hotel.
2. A Nokia E65
3. Pairing it with the Nokia was a cakewalk. Getting it to connect to my Mobile Telco however was hell. Customer services were Kafka-esque in their explanations which didn't help. Got it done in the end by modifying the connection strings.
4. 3 UK
5. I'm using the X-Series Silver which costs me £35 a month with unlimited internet and a load of free minutes and messages. When I can't use my n800, I just use my E65 to surf and check e-mail.
6. 3 officialy will not let you use your mobile as a modem. However, this is incredibly hard to monitor. Still though, if you have a My3 account on their website, use that to monitor your data usage daily.