[1.1.3 OTB] How do you downgrade to 1.1.1 and jailbreak using Mac?

Hi guys,

Would love a Mac tutorial or links for info regarding a 1.1.1 downgrade for 1.1.3 OTB iPhones and the jailbreak info.

Sorry if this question has been answered elsewhere in the forum but I can only find the iBrickr method.

Thanks in advance.