I wasn't sure where to post this since there is no general forum for cellphone (non carrier specific) but given I am a 2D customer and planning to visit the US over Christmas and probably not roam, I thought I would post here.
Anyway after looking at the two carriers I could use to roam, viz. AT&T and T-Mobile I decided to go with T-Mobile. It wasn't entirely clear how their plans worked so I called them to ask and signed up.
They have two prepaid plan types. One is like 2D's monthly plans (no contract but you pay in advance) and the other is more like a Pay as you Go type plan. For example for $30 you get 160 minutes of talk, messages cost 5c to receive and 10c to send. For the big texters they have a monthly plan of $15 for unlimited texts and 10c/minute for calls. That would go down well here I would imagine!
I decided that a monthly plan was good for me. I chose the option of US$30/month which provides for 1500 minutes talk and text (mix and match I guess) and 30MB of data. The CSR said while I could buy the SIM card in a T-Mobile store, he recommended I purchase it with him and save money. The stores could charge up to $30 for the SIM(!) whereas he would sell it to me for $7.42 including shipping and tax to a US address.
Extra data is $10/100MB (but it lasts only 7 days) or $30/300MB for 30 days but I think I can live with 30MB. The main usage of data wil be for Google Maps navigation I suspect and e-mail.
I did that and it will be waiting for me when I arrive. The SIM comes with 10 minute of complimentary time but he also recommended that I activate the SIM and put the money on it using a landline since even calling a toll-free number from a cellphone incurs airtime charges and that 10 minutes would be used up easily.
So all in all a very good customer experience. Since I only will be in the US for just under 3 weeks, I won't be renewing the plan of course. And I don't care what number they assign me since I plan to tell people my Google Voice number and have GV route calls to the cellphone number. My 2D phone will have a message telling people to call my GV number.
Just some notes for others who might be planning to visit the US and are looking at local SIM options.