I'm heading over to the States in a couple of weeks. I'll be there for over a month, and will probably end up using the wifi at the various hotels for my basic communications - email, online banking, browsing, etc. I'm wondering about security though. Someone has suggested that I should use a VPN, however I don't know much about VPN. From what I understand, it sets up a private network between two or more computers, separate from the public wifi network. This seems useful if I needed to "dial home" to access my files on my home computer. But if just want to be secure on the public wifi, how would this help? Or do I just need to take the usual security precautions: turn off file and printer sharing, firewall on, and ensure that https/SSL is in use on my email (outlook.com) and online banking sites. Or is there something else I should be doing to be secure on public wifi?
The other option I'm exploring is getting a SIM card for my iPhone (current favourite is T-Mobile's Pay As You Go), and tethering that to my netbook. How secure would this be, and what security precautions should I take?