1. just normal wear and tear
2. yes - mines gets it after a few thousand (one of the reasons I fitted a scottoiler)
3. if the chain clears the front sprocket without catching then you're ok. It will get progressively noiser as the 'curl' gets deeper tho.
4. I don't know, think mine currently a DID (which is original make, rebranded to ducati)
5. try mandp.co.uk, thefastone.co.uk and ebay (not ducati!!)
6. Normally yes.
http://www.thefastone.co.uk/products.asp?cat=57 I have the bottom one on that page. It does it's job but they're all cheaply made so don't expect it to last more than 4-5 changes before u bend the pin (most come with spares)
[Edited on 30-4-2006 by moozaad]