Google released new gmail on mobile application. It can access whole archive, and send emails to anyone in my contacts list — through an interface that’s very familiar. Check out the new version in the  phone’s browser http://gmail.com/app.
The application is pretty faster than old one. It support almost all j2me based devices. They have seperate application for blackberry. The main features are listed below.

• more than 30 percent faster overall, and 80 percent faster for some tasks
• a contacts viewer to view your all Gmail contacts and addresses
• an outgoing mail footer to let your recipients know you’ve sent an email from a mobile device
• click-to-call phone numbers which you can call without retyping the number
• emails are saved for later re-editing if connection drops or if you want to perform another task before sending out the message
• Gmail keyboard shortcuts to perform tasks faster (on phones with full keyboards).