I\'ve installed mongodb and have been able to run it, work with it, do simple DB read / write type stuff. Now I\'m trying to set up my Mac to run mongod as a service.
I did a bit of looking around on the Mac side. You may want to use the installer here as it looks like it does all the setup for you to automatically launch on Mac OS. The only downside is it looks like it's using a pretty old mongo version.
This link here also explains the setup to get mongo automatically launching as a background service on the Mac.