The typical way that you would distribute a Mac app like this is to create the app bundle, then create a disk image file (dmg) using Disk Utility, and put a copy of of the app inside the disk image. Mac users are very well versed in opening a DMG (which mounts the disk on their desktop) and dragging the app to the Applications folder to install it on their hard drive. The eBay tool JBidwatcher, which is written in Java, is distributed for Mac in this way, as well as an exe for Windows or as a plain Jar for people who enjoy the Star Wars prequels.