Apple - How to show iOS screen on a projector like Steve Jobs did on his keynotes?

About the iPhone/iPad frame images - they are available when you're a registered iOS developer: http://developer.apple.com/appstore/resources/marketing/ They are a very high quality Photoshop files (for printing and for screen use).

In the past Steve has used a specially modified iPad and iPhone for screen display, tethered with an on-stge cord. The iPad 2 has been widely reported to do screen mirroring via the Apple HDMI adaptor. For your purposes, the iPad 2 would seem to be the best choice.

Exclusive to the iPad 2 that will be hailed by educators, presenters, and anyone else who has ever wanted to show off their iPad’s screen to a large crowd: video mirroring. When connected to the HDMI adapter, the iPad 2 will display a duplicate version of the contents of its screen on an external monitor. Want to demo an education app via a projector or HDTV for a classroom full of kids? The iPad 2 makes it possible.

In mirroring mode, the iPad’s interface is crystal clear. It looks great. Because the iPad’s video interface is a 4:3 aspect ratio, you’ll find black bars on the sides of the TV when in mirroring mode. The bars grow even wider if you put the iPad in portrait orientation, but the image of an iPad 2 in portrait mode still looks good—albeit smaller—on an HDTV.

There are many iOS devices (some with previous generation hardware and running older iOS).

If the original question is referring to iPad, iPad 2, iPod Touch 4th Generation, and iPhone 4, there are now two new optional Apple accessories available at Apple Store (US).

Both allows video out (up to 1080p and mirroring for iPad 2; up to 720p with no mirroring for the rest i.e. iPad, iPod Touch 4th gen, and iPhone 4):

• Digital AV Adapter
• Apple VGA Adapter