Google mobile has added two improvements that will speed up mobile Gmail for Android phones and iPhones/iPod Touch.
The first improvement is faster address auto-completion. Gmail for mobile will quickly display possible contacts once typing is started. They made it faster by reusing previously fetched matches in subsequent searches.
The second improvement is keyboard shortcuts for Android-powered devices with a physical keyboard. Gmail keyboard shortcuts allows users to quickly move through the inbox. While reading an email you can press 'u' to return to the inbox or 'n' to move to the next conversation.
To try out Gmail for mobile, visit gmail.com in your mobile browser. This version of Gmail for mobile supports iPhone/iPod Touch OS 2.2.1 or above, as well as all Android-powered devices, and is available for US English only.