Heh... sketchyness is my friend, as I'm certain you're aware if you visit my webcomic. :-) Though I tend to employ a different sort of sketchyness, I think I can say that inqing your pics wouldn't hurt them at all. Just use a thin pen to make it happen. In fact, with lines like you have in the comic, it might add something to it if you keep both the ink and the sketchy pencil.

The second one, though... that comes from a GroupBoard or similar impliment of destruction, right? I'd say smooth that one out a bit. Pencil sketchyness looks better than computer scketchyness, I reckon...

But anyhoo, good comic for a start. Nifty attention to detail for five panels. Just remember, vector objects (or Bezier paths in GIMP) are your friend for word balloons. :-)