Within the rich diversity of these provinces and the many unique places I would recommend you browse through as many sites as possible to check information:
http://www.turismo.gov.ar/g/mapas/sal.htm The Province of Salta´s links organized by Argentine National Tourist Board. Lots of useful info of how to get, where to stay, things to do, what to visit, shopping etc
http://www.salta.gov.ar/turismo - Salta´s province official site with general info, government departments, tourism, production, people´s feedback, statistics and links
http://www.turismosalta.com Salta´s local site with links to diverse information, geographical divisions, touristic itineraries and schedules, local craft and art, typical meals, tourism risks, transport and recreation
http://www.iruya.com/ - another Salta´s local site with lots of local info but some very interesting data for tourists; get to know their cultural life and have a feeling of what they are doing.
http://redsalta.com - Everthing you want and need to know about Salta
http://www.movitrack.com.ar - Adventure at full speed. Unique safaris and trips. Don´t miss.
http://www.redsalta.com/arnaga/ - Arnaga´s site within the Redsalta
http://iruya.com./ent/selvamontana/ - Selva Montana´s country accommodation
http://www.redsalta.com/molinos - Hostal Provincial de Molinos
http://www.redsalta.com/eatonplace/english.htm - Eaton Place Country residence
http://www.redsalta.com/loslos/ - Redsalta´s link to Los Los accommodations
http://redsalta.com/guia/alojamiento.htm - Red Salta´s selected accommodations info
http://www.megasur.com/arg/juju/ The Province of Jujuy local site with stories of travellers, statistical data, provincial events, hotels and accommodation, photographs and maps
http://www.tucuman-ar.com/indexing.htm - The Province of Tucuman local site with Spanish and English text.