My girlfriend recently bought me Artrage . Great and affordable art package based around emulating traditional brushes/pens. I'm having lots of fun with it so far. It's simpler to use than photoshop if doing straight artwork so my plan is to use it in a general workflow, doing the main design, shading, colouring in artrage then taking over to PS to add any more final touches (textures, level adjustment etc).
Here's a sketch anyway done in Artrage. (first quick sketch but I'm happy enough with it!)
Edit: Just tweaked a in PS for a little more contrast and gave it a subtle tone. (see below)