Viewing YouTube in slow motion?

[Marc Shapiro <marcnshap@gmail.com>]

Is there any software out there to allow me to download, or capture the 
stream of a YouTube video and then play it back at a slower pace.  There 
are some videos of karate katas that I would really like to view at 
about half speed, or slower.

Continually hitting the pause button helps some, but is not really the 
best solution.

Marc