The Painting Clinic (a good site in itself) has an excellent tank weathering tutorial for Flames of War tank painters.
I have an entire 1500pts German DAK army to paint that’s currently living in a shoebox in my garage, so might try adapting some of these techniques to a desert scheme.
As an aside regular visitors may notice I’ve been posting more links and less of my own work recently. I’ve got plenty of projects on the go, but nothing that’s reached a point that’s worth posting imho! Next week I hope to be revealing some nifty projects.