If you want to be part of the unofficial beta team for the iOS version of GMail, you can grab it here. Note that it apparently isn’t showing up in iTunes searches, at least from my iPad.
Here is the description:
Get the official Gmail experience for your iPhone, iPad, or iPod touch.
With the Gmail app, you can:
● Receive notification badges for new messages
● Read your mail with threaded conversations
● Organize your mail by archiving, labeling, starring, deleting, and reporting spam
● Keep track of important messages with priority inbox
● Auto-complete contact names as you type
● Send and receive attachments
● Search through all your mail
The Gmail app is available for devices running iOS 4+.
I call it a ‘beta’, but that isn’t the official term. It barfs up a cryptic error on starting for the first time, ignores the notification system, and uses a ill-fitted web page for login. On the upside the UI design for the app looks very solid, using the new visual style but more efficiently laid out than something like Google Reader. If you live in GMail it is definitely worth a look!
UPDATE: Google has pulled the GMail app because it is a disastrous buggy mess. I know they are a company that prides themselves on using the public as the main source of software QA, but this is ridiculous even for them!