My brother knows I'm the "phone maven" in the family and asked me to set him up with a phone to use in Argentina. Turns out he may be going there on business at least 2 or 3 times this year.
I went to the www.telestial.com web site and they sell the above SIM for $35US. It includes about $3US in credits. In addition you get a voucher w. which to had another $10US in air time. That means the SIM only cost about $17.
[I ordered it New Year's eve and it arrived the 2nd business day after the long weekend.]

How does one notify a moderator w. updated info on a product?

SIM is good for 8 months from first use - recharging adds 8 months fm. the date of recharge. The coverage map on GSM world only shows coverage in Buenos Aires. Coverage on the Personal web site (which you can get to simply by clicking on the picture of the card here) shows fairly wide spread coverage. The system operates on both 850 and 1900 depending on location.
Cost seems to be (in U.S.) 33/26? peak/off peak to call back to U.S. - VERY reasonable. Peak calls w. in the country are about the same! - 29?.

I ordered this in advance so he can give his office and the people he will be seeing his number before he gets there. Since he won't be there until Feb., I won't be able to report back on coverage and quality. He will be using a virtually new Moto V188 quad band i was keeping on hand as a back up. (He uses Verizon here, which is why he didn't have a GSM phone.)

I wonder if Personal recently bought up or combined w. another company since the coverage map on Telestial's site also shows only the same limited coverage as GSMworld. The sales person at Telestial said this was a new product for them and they hadn't updated the site.

Thanks for the review, keep us updated when you have news. The coverage is expending very fastly thanks to the GSM 850 band, I think GSM-World needs a big update...

I'm new to this international stuff, so forgive the simple question.
I, too, am on my way to Argentina soon and already own a Nokia 3100 with a UK-based SIM card. But I'll be in Argentina (mostly Buenos Aires) for at least two months. As I look to buy a SIM from some sites, many of the SIMS say you must have a GSM 850/1900 phone. Others don't mention what type of phone you need.
The Nokia 3100 is EGSM 900, GSM 1800 & GSM 1900. Will that do, or does it have to be exactly GSM 850/1900?
Thanks in advance.
GSMN

It will do but with a limited coverage to only the 1900 band.
Most likely the big cities will be covered but not the countryside (As it is in the US as well).

Chris

I've noticed that the coverage maps on GSM-World are quite often not as up to date as the networks' websites

That's certainly possible, but we have rural GSM 1900 coverage here in Canada on Rogers (in addition to GSM 850). Rogers did that so that the early GSM adopters who have GSM 1900 (or 900/1800/1900) phones would have nationwide coverage.

All very helpful, thanks. As I said, I'm very new to all of this.

Follow-up questions:

1. from the coverage maps i've found, there's one provider who has far more coverage around Argentina than the others: CTI Compania de Telefonos del Interior S.A. (CTI Movil). In order to get their vastly superior coverage, does it matter whose SIM i buy? or is it all just determined by roaming?

2. If i buy a SIM card for Argentina, how do I get voicemail? is voicemail something that I get as a result of buying a SIM card (with the Argentina number it comes for)?

Thanks again,

GSMN

1. If you want that coverage that CTI Movil provides you have to buy that sim card.

2. It depends on the carrier. In the UK and most if not all the EU countries have voicemail in some of the Russian Block countries it is a seperate service that you have to pay for. Not sure about South Americia as I do not travel there.

Update on Personal Early 2011
 

Found Personal to be a convenient/fast solution for calls/internet access.

1.- SIM may be purchased w/o hassle at many street press stands. Look for signs reading "venta de chips personal, movistar, claro" Price 12 Pesos (some 2 EUR).

2.- As sold chip holds no credit. Recharge with min 15 Pesos (carga virtual) or min 25 pesos (scratch card).

3.- To activate dial *151

4.- Purchase Pack "Todo incluido" for 15 Pesos to get 25 Mb to use in 7 days. To do so choose "Autogestión/Comprar Pack/Pack todo incluido" in the Personal Sim menu.

5.- Find an international phone card with a local access number / use voipbuster, etc. and choose the access number as a "número amigo". Use *152 to this end. Then buy pack "llamadas número amigo" to get 12 hours of calls to that number to use in 5 days. Price 9 pesos.

6.- All in all everything you need to stay in touch in Argentina for a week for about 7 EUR. On my Blackberry 8520 (no 3g), I got EDGE in BsAs and EDGE or GPRS in Calafate and Iguazú. :D