Gmail has been redesigned today for mobile safari users to offer a faster and better experience. If you use Gmail via the website on your iPhone, you will notice a few improvements that would make it feel more like a native app.
The scrolling speed has been improved which means that you can now scroll through long conversations instantly. The layout is now a bit changed and a toolbar always sticks to the top giving you instant access to features like delete, archive etc.
via [Gmail Blog]