Not Just for iPad Anymore
Keynote on iOS (along with the other iWork apps) was originally released just for the iPad. That situation changed in June 2011 with the release of version 1.4, which made the apps universal, bringing support for the iPhone (iPhone 3GS and later) and iPod touch. Basically, any iOS device that supports iOS version 4.2 or later will run the iWork for iOS programs just fine. Realistically, this improvement means that you can play Keynote presentations with your iPhone (using the Dock connector to the VGA adapter), although the phone's small screen pretty much limits you to minor slide edits (see Figure 9).
Figure 9 The small size of the iPhone screen isn't conducive to a lot of text edits.