If all your app does is open a site on the browser, prepare to have your app rejected by Apple. They don't want apps that are simply fronts for web sites. Be sure to read through the App Store Review Guidelines.
If your app opens in a browser, then it's probably a web app which you can download using Safari on your iPhone. If it includes a manifest, you can "clip" the app so that it will have an icon on your iPhone allowing you to run the app offline just like an App store app. No need to submit it anywhere to have it download and run on any iPhone.