Installing an iMovie on the iPad has become very easy now. The MacRumors has given a set of instruction how to install iMovie 1.2 on the first-generation iPad and more interestingly without even jailbreaking.

First off, make sure you have the actual iMovie app. It’s available at $4.99 in the App Store. From iTunes right-click on the app and “Show in Finder”. From the Finder window, drag the app on your desktop.
Change the apps extension from .ipa to .zip. Double click on the .zip file, navigate to iMovie/Payload and drag the iMovie.app file from the folder to your desktop. You can delete the other files and folders. The iMovie.app is the file we’re going to install on the iPad.

Connect you iPad via USB cable and select your iPad under “Devices”.
Now go the Application Tab and hit the “Install” button to install iMovie 1.2 on your iPad. Before doing all thing you must check it out iPhone Apps Gallery and iPad Apps Gallery to find more apps for your iDevice.
for info, iMovie now available on iPad2