How to call Argentina from the USA/Canada:

dial 011 + 54 + phone number

Calling from another country?

The time in Argentina is now 03:48:20pm

011 - US exit code; dial first for international calls made from the USA or Canada
54 - Country Code for Argentina
Phone Number (may not begin with 0) - 10 digits for both landlines and cell phones, area code included
sample call from US to a landline in Buenos Aires: 011 54 11 ???? ????

add digit 9 (nine) between the country code (54) and the area code of the city you are calling; you will have 011 + 54 + 9 + ten digits.
if the cell number begins with 15 you must drop these two digits and add the area code instead
example #1: you want to dial a cell phone in Bahia Blanca; this is what you will dial from the US: 011 54 9 291 ??? ????
example #2: someone from Buenos Aires gives you a cell number of the format 15 ???? ????; you will replace 15 with the area code of Buenos Aires (11) and dial the following: 011 54 9 11 ???? ????

Buenos Aires	11	La Rioja	380	Salta	387
Bahia Blanca	291	Mar del Plata	223	San Juan	264
Catamarca	383	Mendoza	261	San Luis	266
Comodoro Rivadavia	297	Mercedes/Prov. B.A.	2324	San Nicolas	336
Concordia	345	Neuquen	299	San Rafael	260
Cordoba	351	Parana	343	Santa Fe	342
Corrientes	379	Posadas	376	Santiago del Estero	385
formosa	370	Resistencia	362	Santo Tome	3756
Jesus Maria	3525	Rio Cuarto	358	Tandil	249
La Plata	221	Rosario	341	Trelew	280
Click here for a comprehensive area code list for Argentina

Paginas Amarillas - several directories for business and people searches (in Spanish)
Telexplorer - reverse search by number (in Spanish)