This step-by-step procedure will show you how to make a DMG package from the GNS3 source code. I’ve built the package on Mac OS X Snow Leopard and used Py2app to make a Mac OS X application. Also, have a look at this article that really helped me.

This procedure worked for me, please let me know if you encounter any issue and I’ll update it. Also, please tell me if you can make it work on Mac OS X Leopard (10.5.x).

» Read more: Making a DMG package

Here are instructions to run GNS3 from the sources (not the standalone compiled DMG version) on your favorite operating system. You will have to install or compile dependencies like Qt, Sip and PyQt. This will allow you to use the latest development version of GNS3 that you can download from http://code.gns3.net.

» Read more: How to run GNS3 on Mac OS X