Recently I discovered that Sitting Ducks is back on the air in the US! It's on qubo digital six times a day Monday through Saturday:
It's a broadcast channel, so all you need to pick it up is a TV antenna. However because it's digital you also need a digital receiver, but this may be built into your TV already if it's fairly new. You can find out more information about what you need here:
Here are the stations that broadcast qubo digital:
I was able to just buy a $20 indoor antenna and start watching! Joy!
BTW, if there isn't a station in your area, you can purchase the following DVDs:
Sitting Ducks Season 1 Quack Pack: http://www.tv.com/sitting-ducks/show/19422/dvd.html
Duck Cravings: http://www.dvd.net.au/review.cgi?review_id=2008
Ducktown Adventures: http://www.dvd.net.au/review.cgi?review_id=2365
The latter two DVDs are Region 4 PAL, so you need a region-free player that does NTSC/PAL conversion in order to view them. It's also possible to convert the discs to region-free NTSC DVDs you can play in US players, although it's not a simple process.
Hope this helps other fans out there!