via:monospacedfirefoxtoolsosxdevelopmenttestingDave Martorana | MultiFirefox 2.2
Dave Martorana | MultiFirefox 2.2 davemartorana.com
A small launcher utility that allows you to run multiple versions of Firefox side-by-side. It helps you set up multiple profiles (one or more for each version of Firefox), remembers your last launch preferences for easy launching, has auto-updating built in for when we make improvements, and is 100% open source, MIT licensed.