We stayed in a beach town called Bagamoyo which is about an hour or so from Dar, if I recall correctly.
http://www.bagamoyo.org/bagbeach.htm I think that is the one we stayed at. Right on the beach, good rooms, don't remember it being so expensive. I should mention that this was all part of a study abroad program with Uni so it was all a lump sum! We also went up to Arusha (flew) and saw Mount Meru and from there went to the Crater and stayed in a swank hotel. I don't remember the name of it but this is the name of the reserves we went to
Mikumi Wildlife Reserve, some 170 miles or so west of Dar-es-Salaam; Saadani National Park about 60 miles north of Dar-es-Salaam. I think the name of the hotel in Zanzi was La Plage de Mer? It was in Spice Town. Go to the Africa Hotel and buy a bloody mary-best one I have ever had!
This is the website to my uni's study abroad page as well...I will try to contact my old teacher and ask him if he remembers the other hotels we stayed in!
http://appl027.lsu.edu/artsci/fllweb.nsf/$Content/Swahili.Study+Abroad?OpenDocument
I hope you enjoy it...I really love Africa and Tanzania is one of the most amazing, beautiful places...Trying to convince DH to move to Zanzi one day