Though Apple left the original iPad out of the iPhoto party it's still possible to install and run the app using the iPhone Configuration Utility. The utility is designed to configure and install apps on iOS devices used in enterprise environments, and can be used to install apps that would otherwise be limited by the App Store or iTunes.
Apple has limited iPhoto for iOS to the iPad 2, iPad 3, iPhone 4, and iPhone 4S. Despite having the same A4 processor as the iPhone 4, however, Apple has excluded the original iPad as well as the latest iPod touch. The limitation may be due to RAM—both of those devices only have 256MB of RAM while the iPhone 4 has 512MB, and RAM is important for loading images as large as 19MP.
One user discovered that with a little prodding, iPhoto can be installed and run on an original iPad. Peter Emery, a semi-retired communications technician from Australia, discovered that he was able to install iPhoto on an original iPad using Apple's iPhone Configuration Utility. Emery had used the trick previously to install and run iMovie on an iPhone 3GS, which technically isn't supported by Apple.
The trick hasn't been confirmed to work with the iPod Touch, but Emery told Ars that he believed it should still work. Emery was also not able to verify if the trick would work with the new Lion-only Apple Configurator available from the Mac App Store, though again, it is believed it should work.
If you try installing and running iPhoto on an iPad or A4-equipped iPod touch, let us know about your results in the comments.