Actually caught an old thread about this very subject via Google, which had the (normally) useful solution to copy the URL of a video stream from the Activity Monitor in Safari.
Well, for some reason this particular stream isn't showing up in the Activity Monitor, so it's back to the URL sniffer question. Does a free Mac one exist?
Of course, if you can hook me up with the URL, that works too. It's for the Justin TV feed of TWiT Live. If you click the link, the Justin TV stream should load. The Bitgravity stream shows up in the Activity Monitor, so I have that URL, but it's unstable, which is why I want to use the Justin TV feed.
TWiT Live - netcasts you love, from people you trust