There are many different types of Softphone. Before choosing which type of softphone you want to use, you need to decide on what VOIP service provider you are going to use. This depends on how much you are prepared to pay a month (if anything), and the quality of service which you would like. It also depends on how many phone calls you are going to want to make outside of the VOIP system (such as to normal standard telephone lines), the country in which you live in and the countries in which you want to be able to make calls to.