How can I export my iPhoto library so I can import it on another computer?
Everything in your iPhoto Library is stored in ~/Pictures/iPhoto Library.aplibrary (note that the extension is hidden by default).

Simply copy that file to whatever Mac you'd like to move it to. Just make sure you are running the same version of iPhoto in both cases to minimize incompatibility and error.

Apple has an article about moving it if you are interested.