If you don't want to install the entire iLife '05 package, you can custom install one or more applications from the iLife CD or DVD. Here's how:
If you're trying to reinstall an application but it appears dimmed in the custom install list, quit the installer, delete the item from the Applications folder, and delete its associated receipt files from /Library/Receipts/. Then reopen the iLife installer and try custom installing again.
Important: After installation is complete, immediately use Software Update to make sure that all the applications are up to date before you launch them.