Metasploit and OSX

Hi Guys

So I have done some hacking with Metasploit and Windows (the malicious .mcl file) and I was wondering how I can open a meterpreter session on OSX. I have looked at the exploits in metasploit (search for OSX) and I have found one that requires you to put set a SESSION. Any pointers on what this is? Also what should I look for in a payload and how can i further my knowledge on the different exploits for OSX in metasploit so I know how to use each. Someone in the know should make some How-To's on this!! It would be a great addition to the null-byte library as all we have now is a tutorial on creating a backdoor (And there are no instructions on how to do remotely via a malicious file, vulnerable port or any other kind of exploit.)

Thanks !!