5pm iPhone app is available for free to all 5pm users, through iTunes:
http://itunes.apple.com/us/app/5pm/id497918477It supports the main view and edit functions and can help you access 5pm on the go.
Supported features:

Swipe Right to see the Global Menu.
Global menu gives you access to:

Swipe Down to reveal useful filters:

Swipe Left on Messages to see access Reply, Edit and Delete options.

Swipe Left on Tasks to access Mark as Done, Edit and Delete options.