Willysnout - re: GSM phones...Just a heads up - a lot of the GSM tri-band phones sold in Morocco do not work in the U.S. with major plans. I'm not entirely sure, but I think that the phones here (Morocco) are no different from those sold in Europe (definitely not different from those sold in Spain). Nearly every Moroccan I've spoken to who has tried to use their phone in the US with an American SIM card reported failure.

What about Boost mobile? Good/Bad/Ok?
I'm travelling from San Francisco to New York via the South and they seem to have pretty good coverage. Although I'm thinking they're maybe CDMA because they talk about iDEN 800...

if you are gouing to use a US SIM card in your own phone, you need to be sure your phone is a tri-band and is unlocked - maybe that's why those Moroccan phones didn't work.

Boost uses the Nextel network - you're right that it's iDen, which is neither CDMA or GSM. It's a third thing entirely, and not compatible with either of the other two. It uses SIM cards, but they are incompatible with GSM SIM cards. They're special iDEN SIM cards.
Nextel's coverage isn't great. I wouldn't immediately recommend them unless you plan to use their "chirp" push to talk system with your homies.

#12, I know - the phones should be unlocked, since most phones in Morocco are purchased as-is, without contract or particular carrier, and they're definitely tri-band. Who knows why they didn't work...

iDEN is kind of a niche product, and it does what it does pretty well. It's history is a bit different, and as a result, the product today is a bit different. It came out of the two-way radio industry. What it does well is provide integrated dispatch functions. Sitting here in St. Paul, I can hit the push to talk button and talk to Brazil or Hawaii. Pretty cool, really, as there isnt the lag time that the push to talk function other carriers use.
However, iDEN still has not moved much out of its early market--contractors, delivery people, etc. And the handsets kind of reflect that. They are quite rugged, and they are also quite large and bulky.
iDEN is one of several TDMA systems, by the way.

Last summer I bought a Trackfone at Walmart's. Noone has mentioned this company yet. The phone was 20$, the prepaid phone card another 20$. Calling as well as being called, units were discounted very fast, I found.
Would anyone be able to compare Trackfone to the companies mentioned above?