As far as I'm aware the only Hotel offering all inclusive in Salou, is the Villamarina. I might be wrong as we haven't been there in a few years.

Festival Park, mentioned in a previous thread does A/I, a colleague of mine went to the Hotel Calypso in Salou (Skytours brochure) they had a great time and it gets decent reviews in the review section.

Might be worth visiting Thomas Cook/Thomson/First Choice/other tour operators websites, putting in the dates, selecting All Inc, see what hotels are available then checking out the reviews on here.