A few sci-fi webcomics have been making the rounds recently—
Escape from Planet Nowhere by Otis Frampton
Spacedock 7 is a portal to 7 webcomics. Each update weekly.
Spacetrawler by Christopher Baldwin updates Mondays and Wednesdays.
Giannis Milonogiannis presents OLD CITY BLUES, a monthly sci-fi police thriller webcomic. We've highlighted his work in the past.