Ok, I think I got it. I'll try out. Thanks!
Now, another doubt.. on the CMUcam manual, it's said that the packet sent back comes in ASCII viewable format. On the LCD, for example, it comes as something like "T 23 12 52 42 ..". But, how does it arrives to the Arduino? Is it in Decimal, Hex? I can't monitor it on the Serial Monitor, because Duemilanove has only one Serial Port.