Google had added a new feature called Priority Inbox for Gmail which would help you sort out important emails based on machine intelligence and user input. It looks like their in-house OS Android is the first device to get the feature.
The new Gmail App for Android has a sticky action area, which contains important actions and will stay on top of the message even when you have to scroll through a large message, giving you an option to quickly reply or star emails. In addition to that, the new app also makes it easier to view previous messages in a conversation.
Gmail for Android also has limited integration with Priority Inbox. If you have enabled Priority Inbox through the desktop version of Gmail, you will see a new label called "Important" which will display all Priority messages to you. You can also set up a shortcut on your home screen for the "Important" label.
Another important new thing about the new Gmail App for Android is that it is no longer tied to the Android OS and will receive standalone updates, so users no longer have to wait for an Android update to see an update to the Gmail App.
The latest Gmail App for Android will only work on Android 2.2 Froyo devices. If you don’t have an update yet, you will have to wait till you get it. The app can be downloaded from the Android Market.
More info and details at the official Google Mobile Blog.