Zita the Space Girl is a series of charming short webcomics by Ben Hatke.
Hatke draws Zita with a simple, somewhat cartoony outline style reminiscent of early 20th Century newspaper comics, and occasional elaborations with atmospheric color.
The bad news is that Zita is updated very infrequently (although not as infrequently as, *Ahem!*, certain other webcomics are updated). The good news is that Hatke is working on new Zita material for print.
Hatke has been a contributor to the Flight comics anthologies (see previews here and here) and is working on a Zita strip for inclusion in #4. There is a nice write-up on the Flight blog that goes into more detail including the origins of the character and initial designs.