New Shiur

A simply eye opening shiur [number 1500 BS"D!!] on giving mechila to your friend from the holy Rav Hutner זצ"ל, here and here.
The Rambam teaches the same halacha in 3 different places with significant changes. See also how the Lubavitcher Rebbe deals with this in the sefer Shaarei Ahavas Yisrael [from page 307]. Also see Vi-atah Birachamecha Harabim [R' Ginzburg page 72], Dvir Kodsho [page 73].