So, I have an idea for a mobile app (thinking specifically for android and iphone. It really has to be used mobile, on the go. But, I'm not sure where the technology is. Is that still the bread and butter way to go, or could a nice "mobile site" developed in html 5 do the trick and cover all phone platforms, and still reach the users? It would need to access the phones GPS for locating, and offer a shopping cart and messaging system between users. I'm totally green on this, but it sounds like developing an app for apple and getting it approved could be very costly and time consuming.
To get the best user experience, native (android or iphone) is definitely the way to go. The major problems with going native is that it can be very time consuming, expensive, and requires you to write in two completely different languages and platforms. With that being said you have two other options. Build out an HTML5 app that would run in the browser. You can access geolocation (GPS) via Javascript, and pretty much any other capabilities you have in your desktop browser are available in your handheld as well. For this you might want to take a look at jquery mobile. Another option is to use phone gap. Although I haven't personally tried it out yet, phone gap gives you the ability to write html,css and javascript, and then compile it so your app can be ran on multiple platforms. It seems like some awesome technology and it's growing very quickly.
Thank you for this information. Very interesting stuff. What I'm wanting to do with GPS is, say there are 10 people logged into the site/app. Their device needs to use their own GPS abilities, and track and locate where they are on a map. Each person should be able to see their own location on the map, as well as the other 9 peoples location on the map. It would need to be able to live update as they moved so that say person #1 could move to the location of person #10 on the map (probably walking pace). Aside that from that trick, a basic cart checkout system to transact purchases to the home site (not between parties, but from users to the site owners), and a messaging style system to allow one user to contact another without giving away personal direct contact info like phone # or email address.