The Pentel Arts Pocket Brush Pen is awesome for comic illustrations. I've just used it on a comic for my doodle tumblr blog and the image came out great. I first created the boxes then sketched with a pencil. Then I traced over the drawing with the brush pen and erased any visible pencil marks. The brush is very versatile and can create thick to fine lines. It takes some control but with practice it can be a very handy tool. For some touch ups I also used a Sharpie pen. The pen I ordered from amazon comes with one refill (the pen does not have an ink cartridge in it).
The comic that I drew and scanned into the computer:
Please check out the other comics and follow me if you'd like :)
Link on amazon: