Originally Posted by
VidaNaPraia
Fly into IGU from GIG (Rio) on TAM or GOL, and out of the airport on the Argentine side of the falls, perhaps on an Argentine airline (cheaper that way AFAIK).
It's well worth visiting the falls! How long are you going to travel? Although it's your first time in South America, I wouldn't recommend having too tight schedule as the distances are quite long. You can easily spend weeks in Brazil...