OK, so this comes straight out of the why would you want to do this category, but thanks to the iSmooth Project folks from iJailbreakNow, installing and running iPad-only apps is now possible for the less tech-savvy on a jailbroken iPhone or iPod touch.
The process involves using an app called iTelePad2Pod on your Mac to alter the supported devices metadata of your target iPad app. The modified app is then sent to your iPhone or iPod touch using FTP across OpenSSH (which must be installed on your jailbroken device). It's a fairly straightforward procedure and results in some relatively usable apps. This isn't the first time an iPad app has been installed on an iPhone, the once iPad-only Netflix app had that pleasure courtesy of some clever hackery.
These apps are designed for the larger display of the iPad and users may encounter a problem when a button or dialog breaches the bounds of the iPhone's resolution (960x640 for the iPhone 4). If there's an app that's only available for the iPad and you haven't jumped on the tablet bandwagon yet, you now have a relatively user-friendly option. Read on for a video guide.