HI and Welcome to Apple Discussions...
Is the PhotoBooth icon still in the Dock? If so, click the icon then click; Show in Finder That should take you right to the application. If Finder doesn't show the application, you can reinstall it.
Try reinstalling the application from your install disk.
Insert the Mac OS X Install Disc and double-click the package that installs bundled software or additional software. A package has an icon that looks like an opened box.
Follow the onscreen instructions. If you see a pane with a Customize button, click Customize and select the application you want to install. If you see a pane that lets you choose what to install, click the disclosure triangle beside Applications and select the application you want to install.
If you can’t find the application you’re looking for, you may need to reinstall Mac OS X. Your documents and user settings will remain.
Insert the Mac OS X Install Disc and double-click the Install Mac OS X icon. In the pane where you select the destination disk, select your current Mac OS X disk, and click Options. Select “Archive and Install” and “Preserve Users and Network Settings.”
Carolyn 🙂