With Apple’s iOS and Google’s Android mobile OSes dominating the current mobile market right now, it would make perfect sense for a company to develop mobile apps for these 2 major mobile OSes. However, to develop a native mobile app for iOS and another native mobile app for Android, this would incur two tracks of development. This is because the programming languages (in Objective C for iOS and Java for Android) and their IDEs/tools are different and require developers of different expertises.
To keep my post short, there is a good comparison on the pros and codes of native vs. web technologies here: http://interfacethis.com/2011/is-html5-ready-for-prime-time-vs-native/ and many other comparisons that you can find on the Internet. But you will appreciate the differences and trade-offs if you have done both native and PhoneGap development before.
In summary, with PhoneGap, there will be a consistent UI that looks the same on both iOS and Android platforms and there is one main HTML5 codebase to maintain. I will not touch on how to start off coding a PhoneGap app as these are covered on the official site and there are many articles on how to use jQuery UIs with PhoneGap as well.
Things are not that rosy with PhoneGap, as there are still differences and tweaks required on each platform to get PhoneGap working the way you want it to…