Most Android users should be familiar with the stock Gmail app that comes loaded on every Android phone. Now there's an update for Android 2.2 (Froyo) and higher (you must download it manually in the Market app) which adds some additional useful features. Google has decided that incremental Gmail updates should no longer be tied to Android OS releases--a wise choice. After all, some devices will never receive OS updates, so why lock those users out of new Gmail features? Oops, I forgot about Android's fragmentation problem--many devices will never be updated to Android 2.2, either. Tough luck for those users...
The most noticeable difference is apparent when you view a message. There is now a header at the top of the message; it has a button to Star, Reply, Reply All, and Forward, so now you don't have to scroll all the way to the bottom of long messages in order to access those options. The header is supposed to stick to the top of your screen as you scroll, but unfortunately this wasn't the case on my test unit, the Sprint HTC EVO 4G. The header scrolls up out of sight on this device, but Google has promised to update the app to fix the issue.
Another new and useful feature which simplifies reading threaded messages is the option to tap "Show quoted text" to reveal the previous message. I was always annoyed with the older Gmail app's clumsy handling of threaded email conversations, so this is a particularly welcomed addition.
If you have enabled the Gmail Priority Inbox (through Settings in a desktop Web browser), then you will now see an "Important" label that shows all messages flagged as important. You can even add a shortcut to "Important" on your home screen. To do this, long-press on your home screen, Add to Home, Shortcut, Gmail label, Important.
Those are good features to add. However, I am still waiting for Google Docs preview integration, pinch-to-zoom functionality and the ability to create filters. When these features arrive and the header bug is fixed, Gmail for Android will really shine.