In The Sims 3 Island Paradise you can manage resorts in a way that is more or less similar to The Sims 2 Open For Business management. To become a resort owner you should use the phone or select one of the resort lots available. Those special lots must contain a resort tower that is a rabbit hole working as the center of your business.
At the beginning this tower is quite basic, but you can upgrade it if you have the prerequisites and by paying a certain amount of money every time. In this way you can get a better looking resort tower and offer more services to your customers, like SPA treatments.