[jmillet]

If your leather is in relatively good condition and you want to retain the matte finish OE look then Leather Master Soft Cleaner and Leather Protection Cream work well for me. If the leather is dried out or sunburned then revitalizing with Leather Vital works well.
http://www.leatherworldtech.com/
Identify the type of leather you have and treat accordingly
http://www.leatherworldtech.com/Leat...ification.aspx
Most Bimmers have aniline leather. Here is a good tutorial:
http://www.leatherz.com/leathercare2.htm