Some other options for capturing streaming video include rtmpdump which is a command line tool, not for the fainthearted due to complexity, but it can do things like capture the RTE player's encrypted rtmpe video stream. rtmpexmplorer is a front end to rtmpdump that makes it more usable.
In the non-free category are things like Replay Media Catcher, which costs 30 bucks, but I find it good for capturing BBC iPlayer streams (when used with appropriate proxy software to get around the geographical filtering).
Yes, you certainly need to be aware of copyright issues on youtube. The copyright will normally belong to the video uploader, although under youtube T's & C's they grant youtube a non-exclusive right to distribute and monetise. You wil get away with downloading for your own use (who's gonna stop you?), but for public use or re-showing you would by rights need the copyright owner's consent.