Can anyone recommend a wireless carrier based in Brazil that I may obtain service for 1 week and will operate on my BB9900 once I install their SIM card? I need voice and data but don't want to pay the $2.00 per minute charged by AT&T plus expensive data rates while outside the USA. Thanks.

These two have PAYG BlackBerrry data plans:

Telecom Italia Mobile (TIM):
Pré-Pago e Controle - BlackBerry - Internet| TIM

Claro:
Claro | Acesso à internet

You have to remove your BlackBerry from BIS with AT&T before you can get it to work in Brazil IIRC. Unless the PayGo plans work differently. A BlackBerry can only be registered to one BIS plan at a time.

Yes, that is a good point.