Copyright symbol

Hi Max - one way would be to create a jpg image of the symbol (a screen capture of one typed into a Word Document would do), and then add it via cf/x's Picture-in-Clip plug-in:
http://www.imovieplugins.com/index.html
This also allows it to have its transparency adjusted.

Or use the Music Video title option - it will give you 12 seconds max, but you could repeat it if needed, as many times as you require. Music Video places text in either bottom left or right of the screen.

.. or use QuicktimePro to add the ©sign as a watermark to your video..
illustrated HowTo on my ad-free site:
http://karsten.schluter.googlepages.com/watermark

Hi Max - can you explain further? Doing what you suggest has no effect at all when I try it. Do you have to select a particular title-style? Do you have to highlight the clip(s)?..........?
What actually is supposed to happen?

Ah, OK, Max - that's pretty much what I suggested above:
+"Or use the Music Video title option - it will give you 12 seconds max, but you could repeat it if needed, as many times as you require. Music Video places text in either bottom left or right of the screen."+
I just didn't include the Option/G instruction.

I misunderstood you - I thought you were saying that you just had to access the Titles pane, click Option/G and hey presto a © mark appeared on a clip.