Here's a list of the Farscape comics to date:
War Torn (2002) a Wildstorm comics 2 issue series. Not sure where this fits in the timeline.
BOOM! Comics Titles that start after
The Peacekeeper Wars:
The Beginning of the End of the Beginning (2008) the first 4 issue series, which is also available as a collected hardback.
Strange Detractors (2009) 2nd 4 issues series
Gone and Back (2009) 3rd 4 issue series
In November the ongoing series will start. Here's the cover (or at least one of them):

There are also these 4 issue series from BOOM! that are set before
The Peacekeeper Wars:
D'Argo's Trial (2009) which is set before the series started.
D'Argo's Lament (2009) which is set between the 16th "Revenging Angel" and 17th "Fractures!" episodes of Season 3.
There was also a
Farscape Scriptbook (2009) comic book from BOOM! as well. It's basically the outline for the first comic book series. Cool book.