Well, since I waited for 2 days to do this unlock, I used ver 0.9.5. The iPhone 3g was on AT&T activated in the USA. Brought to Argentina was inop. Never before Jailbroken or other thing. I get it working but followed the next steps:

1_IT WAS ON VER 2.0.2 (VINO CON LA VERSIÓN 2.0.2)
2_UPDATED TO 2.2.0 WITH ITUNES 7.7 (LO ACTUALICÉ A LA 2.2.0 CON ITUNES 7.7)
3_ACTIVATED AND JAILBROKEN WITH QUICKPWN 2.2.1 (LO ACTIVÉ Y LIBERÉ CON QUICKPWN 2.2.1)
4_CONNECTED TO WIFI AND TESTED WEB NAV (LE CONECTÉ LA RED WIFI Y PROBÉ QUE NAVEGASE INTERNET)
5_UPDATED CYDIA (LE ACTUALICÉ EL CYDIA)
6_ADDED SOURCE apt9.yellowsn0w.com (LE AGREGUÉ LA FUENTE apt9.yellowsn0w.com)
7_INSTALLED YELLOWSN0W VER 0.9.5 (LE INSTALÉ EL YELLOWSN0W VER 0.9.5)
8_REBOOTED MANY TIMES (LO REBOOTEÉ VARIAS VECES)
9_ IT DIDN'T WORKED (NO FUNCIONÓ)
10_PUT IN DFU AND RESTORED TO FW 2.2.0 WITH ITUNES 7.7 (LO COLOQUÉ EN DFU Y LO RESTAURÉ A 2.2.0 CON ITUNES 7.7)
11_ACTIVATED AND JAILBROKEN WITH QUICKPWN 2.2.1 (LO ACTIVÉ Y LIBERÉ CON QUICKPWN 2.2.1)
12_CONNECTED TO WIFI AND TESTED WEB NAV (LE CONECTÉ LA RED WIFI Y PROBÉ QUE NAVEGASE INTERNET)
13_UPDATED INSTALLER AND COMMUNITY SOURCES (LE HICE LAS ACTUALIZACIONES DEL INSTALER Y DEL COMMUNITY SOURCES)
14_INSTALLED YELLOWSN0W VER 0.9.5 (LE INSTALÉ EL YELLOWSN0W VER 0.9.5)
15_REBOOTED MANY TIMES (LO REBOOTEÉ VARIAS VECES)
16_IT DIDN'T WORKED (NO FUNCIONÓ)
17_INSTALLED OPEN SSH FROM CYDIA (LE INSTALÉ EL OPENSSH DESDE CYDIA)
18_BUCKUPED YELLOWSN0W FOLLOWING DIRECTIONS IN http://www.hackthatphone.com/20/quic..._iphone_2.html (LE BACKUPEÉ EL YELLOWSN0W SIGUIENDO LAS DIRECTIVAS DE http://www.hackthatphone.com/20/quic..._iphone_2.html)
19_CHANGED YELLOWSN0W WITH WINSCP (LE CAMBIÉ INTERNAMENTE EL YELLOWSN0W CON WINSCP)
20_REBOOTED MANY TIMES (LO REBOOTEÉ VARIAS VECES)
21_IT DIDN'T WORKED (NO FUNCIONÓ)
22_UNISTALLED YELLOWSN0W (LE DESINSTALÉ EL YELLOSN0W)
23_UPDATED INSTALLER (LE ACTUALICÉ EL INSTALER)
24_INSTALLED YELLOWSN0W VER 0.9.5 (LE INSTALÉ EL YELLOWSN0W VER 0.9.5)
25_REBOOTED MANY TIMES (LO REBOOTEÉ VARIAS VECES)
26_IT DIDN'T WORKED (NO FUNCIONÓ)
27_PUT IN AIRPLANE MODE FOR 10 SEC (LO COLOQUÉ EN AIRPLANE MODE POR 10 SEG)
28_IT WORKED (FUNCIONÓ)
28_TESTED WITH PERSOSNAL, MOVISTAR AND CLARO SIM'S. NO NEED TO REBOOT BTWEEN CHANGES. ONLY IF REBOOTED NEED TO PUT IT IN AIRPLANE MODE FOR 10 SEC )PROBADO CON SIM'S DE PERSONAL, MOVISTAR Y CLARO. NO FUÉ NECESARIO REBOOTEAR EN LOS CABIOS DE SIM'S. SOLO SI REBOOTEABA NECESITABA PONER EN MODO AIRPLANE POR 10 SEG)

I HOPE THIS IS USEFULL FOR SOMEONE. REGARDS (ESPERO QUE LE SIRVA A LGUIEN. SALUDOS)

Si lo dejas apagado mucho tiempo no te va
a funcionar el sistema de Airplane Mode.
Tenes que ponerlo en Airplane Mode.
y apagar si o si con BossPrefs.
Power. Reboot.
Y cuando Rebootea lo sacas de Ariplane.

Saludos
Hernan

Updated yellowsn0w from 0.9.5 to 0.9.6 from installer and everything is up and running without need to go into airplane mode. Thanks from ARGENTINA iPhone Dev Team!!!

the part of the phone unlock in argentina works great, but the 3g dont when i try to activate the signal dissapier..