Last year, I entered the digital world of digital art with the help of...Photoshop and Gimp. I'm was little rusty on using these tools with my wacom tablet but I just treated it like it was pixelized pencil and paper. I completed two artworks last year, one for a competition on DevianArt and another for Ichumon.com, and I have a lot of practice pictures done in these digital tools.
Here's some art/sketches done in Photoshop and Gimp:
Porcupine man: inking and line refinement stage (photoshop)
Self-portrait based off of my dragon character. (Gimp)
And my Vistalgian character in her last stages: Coloring and Shading. (note: design is copyrighted)(Photoshop)
Sometimes I draw directly onto the computer (in the case of Porcupine man and seft-portrait) and that will take about two or three weeks to complete. With scanned pictures, like Vistalgia, it will take far less time, almost about a week to complete.