Flights from Rio or São Paulo to IGU: check thr domestic Brazilian airlines TAM, GOL, Azul, Avianca
Local buses run from the town of Foz do Iguacu, Brazil, across the border to the town of Puerto Iguazu, Argentina.
Local buses run from each town, past the airport, out to the park entrance, on either side.
Taxis are also readily available.
On the Brazil side, there is a path to walk and take photos of the falls on the other side mostly, with a walkway into the river at one point.
Near the entrance is an interesting bird park.
On the Argentina side, there is an upper walkway over the tops of the falls, and a lower trail, and some parkland.
No tours really needed, except for boat rides under the falls.
Plenty of hotels in all price ranges in both towns, along the road to the park, and one expensive one inside each side of the park.
Just Google for more info.

For Rio, take a thorough look at www.ipanema.com