The app is launching as an iOS app and a web app (that you can find at float.com). The app will also have a bookmarklet so you can save content to the app from elsewhere on the web. There's going to be an Android app, and it should be coming in October.
According to the press release, it has a pretty impressive feature set. Float supports both page turn and scrolling, so it should please everyone. You can save content to the app for offline reading, and it will also sync your reading list with the web app at float.com. If you run out f things to read, the app also has a list for articles suggested by your friends on Facebook, Twitter and Scribd.
It promises easy content sharing with Facebook, Twitter, Scribd or email, as well as a dozen customized reading styles. It also has a library that should let you organize all your reading by date, publisher and title.
I haven't seen it yet, but that sounds a lot like Zite, Flipboard, Readability, and others. This sounds interesting, and I'm really looking forward to it.