I sold some shares yesterday and plan to record them as crystallised losses in my 2008 returns. I can't see why not, even though the settlement date isn't until 6 January. The deal date is what's important.
I don't know the answer to your second question but I have a vague recollection of a restriction on the lines you think.
I'm pretty sure that the answer to your third question is yes. They are traded as shares.
The final advice is that you should consult a tax adviser: I'm am amateur like yourself in this area.