I came across an RSS news feed from JPL listing available high-def videos: http://www.jpl.nasa.gov/multimedia/rss/podfeed-hd.xml. The list is a mixture of regular "What's up for [month]" clips and specials/documentaries, and the format is QuickTime (m4v--MPEG4, approx 80 to > 100MB).

The videos I sampled were all excellent. High-def makes a crucial difference in the space genre, because so much of the source material is high-resolution, and crappy old analog TV rendered much of it, to my eye, not worth watching. They seem to have standardized on 1280x768, which is pretty respectable, and for the first time I could actually appreciate videos of such things as MRO stereo imagery rendered into 3D fly-throughs.

It's a news feed so the content will constantly be changing. Here's today's menu:

High-definition (HD) videos from NASA's Jet Propulsion Laboratory feature the latest news on space and science findings from JPL and NASA. Topics include discoveries made by spacecraft studying planets in our solar system, including Mars, Saturn and our home planet, Earth. Missions also study stars and galaxies in our universe.

Video: Explorer 1 -- JPL and the Beginnings of the Space Age
2007 was a year of scientific surprises and major milestones for JPL missions studying Earth, our solar system and distant galaxies.

Video: Europa - Cool Destination for Life?
Where's a great place to look for life in our solar system beyond Earth? Jupiter's moon, Europa, with its warm salty ocean, might be a good place to start.

Video: What's Up for December
Mars and Earth are at their closest this month so now is your best chance to see our planetary neighbor.

Video: What's Up for November
This month you'll have great views of a red planet and a red star. Plus, find out when the Mars rovers are facing Earth.

Video: Backstage Pass to Iapetus
Scientists recently watched on the edge of their seats as close-up images from Saturn's odd moon Iapetus beamed back to Earth. Relive the adventure, as they see photos of the odd black-and-white moon, and try to figure out what caused the unusual color patterns.

Video: What's Up for October
Pull out your telescope to see Saturn's black-and-white moon Iapetus. And there's something for everyone on Halloween: Jupiter for the early crowd and Mars for the late-night trick or treaters.

Video: The Big Thaw
The change over the arctic sea ice is stunning. Between 2005 and this winter, thick ice has been reduced by about the size of Californian and Texas combined. Scientists are tracking the causes.

Video: Dawn, Mission to the Asteroid Belt
The Dawn mission will go to Vesta and Ceres, the two most massive bodies in the asteroid belt. The asteroid belt, a ring of broken-up debris between Mars and Jupiter, is home to some of the last unexplored worlds in the inner solar system.

Video: Mars - A Feast for the Eyes [sweet MRO fly-through]
The Mars Reconnaissance Orbiter is providing unprecedented views as it studies the red planet.

Video: Phoenix Mars Lander - Countdown to Launch
On Saturday August 4, the Mars Phoenix spacecraft launched from Cape Canaveral, Florida.

Video: What's Up for September
It's the 30th anniversary of the Voyager mission and you can see all four planets that Voyager studied in the night sky this month.

Video: Voyager: Inspiring Generations
For 30 years, Voyager has been broadening our view of the solar system and inspiring new generations to explore.
Personal note: Just after Ed Stone talks about Voyager @ Neptune, there are a couple of stills from the Planetary Society's Planetfest 1989. In the first one, the crowded auditorium, I'm sitting near the left edge, vertical-center.

Video: Athlete of the Future
JPL engineers built a futuristic robot that may one day go to the moon.

Video: Looking for Life in All the Right Places
Find out how NASA scientists are gathering exciting clues that will help them pick the best spots to search for possible signs of life beyond Earth.

Enjoy!