Saving flash videos form websites is very simple. You don't need any additional software, all you need is provided by the system, and you only neet three commands on the command line. First find out the PID of the flash plugin. Look for a task like "libflashplayer.so", "npviewer" or "plugin-container". The name depends on the distribution.
Then change to the directory /proc/PID_of_flashplayer/fd/
There is a link which points on a file which name contains "Flash" and is marked deleted. Copy this where you want and rename it in something meaningful with the extension .flv
That's all.

For better understanding an example, like it is now on my PC:
Code:
~> ps -A | grep plugin
 4691 ?        00:02:21 plugin-containe
this means that the PID is 4691.

Code:
~> cd /proc/4691/fd/ && ls -l | grep deleted
lrwx------ 1 username users 64 20. Apr 22:41 16 -> /tmp/FlashXXhJ0V9B (deleted)
the filename is 16. Now just copy it in the home directory and give the name "video.flv"
Code:
/proc/4691/fd> cp 16 ~/video.flv
Done. Watch and be happy. Works on all sites, you only must wait till the video is completely loaded.