PhoneGap isn't about websites, it's about creating mobile hybrid apps. What, specifically, are you trying to do?
Many people find that customers and clients are more used to the idea of native application that they can purchase from an online marketplace. Some companies have just started a convenient new means of practically and economically developing a mobile web application development, dressing it up as a native one and publishing it as though it were a native program.
The fact that you only need to develop one app to launch it for several different platforms saves a lot of time and money.