I'm confused as to what you are asking. If you are asking if there are online tools to help you make apps, then Microsoft has its App Studio you can use. If you are asking if you can package a web app for windows phone, then things get a little more technical. You ARE allowed to write your app in HTML 5 and javascript and use a web browser control to render everything. In this case, everything gets wrapped in one xap file. If you are asking if you can make a web app, host it externally, and then either use a WebBrowserTask or web browser control to just link to your externally hosted app, it is against Microsoft's terms of service to make an app which just "links" to a web site.