Hold on, let me run a search on a high powered cleaner I use on leather (made for leather). and the conditioner. I'll be back with the edit.
http://www.leathermasteruk.com/
http://www.autopia.org/forums/showth...hlight=leather
Want something cheap and easy? For a straight cleaner you can use 6 parts water to one part woolite--altough, you can use it stronger. Your major thing is to buy a leather brush ( a stiff, short bristled brush). I believe the link I gave has Scottwaxes directions (so easy to do). You'll want to follow up with a leather conditioner.
If any of you want something for not that heavily soiled leather, and a quick clean up/condition, I love the Hi-temp cleaner AND conditioner (all in one). It is quick and effective. I like that stuff. Nice bottle it comes in too.
If you want just a cleaner for every few months, the woolite solution is good, and you can condition with anything of your choice really.

Just...that brush is important. It gets all the dirt out.