What sim to use in USA and what travel money card to take?

Anyone know:

1. A cheap mobile sun card that would fit in iPhone 4 that an Aussie could use in the states for a few weeks?

2. Best/ cheapest money/ travellers card to take?

There are only two GSM networks in the US, AT&T and T-Mobile.AT&T has much broader coverage, T-mo is cheaper. There are also resellers like Consumer Cellular. Find a phone store when you get here and see what they have.

For money, most places in the US take Mastercard and Visa, so bring a credit card. For cash, you should be able to use your regular bank card to get cash from machines in the US.