Sometimes a trusty screw driver can be used to lever the chain ring away from the frame so the chain can be pulled out...
You may also be able to disassemble the chainwheels from the spider without removing the crank, get the chain out, and reassemble the crankset, as per Tim B's suggestion.
[Reply posted before reading second page!]
I agree with Tim, at the worst you should only need to take the chain rings off! The chain does not appear to be stuck between the frame and the spider just itself and the chainring. The reason for the problem in the first place is another matter. It sounds like you could have over-streatched your cable, maybe its frayed and with less strands is more prone to stretching or the clamp on the derailure was not tight enough and when you have forced it through it pulled through the clamp! Im not a mechanic but that's what it appears to be to me!
I live close and could give you a hand if you like!
+1 the chain rings should come off.
I've had a similar chain mishap. Basically I just grabbed the chain with my hands and wiggled and jiggled until it popped free. The chain can be pretty tightly jammed in such a place though. A crank extraction tool is not very expensive and pretty easy to use - give it a go!
Good and cheap!
I know a good one, BMCR on Waymouth st.
Cheap, put the bike up-side down and wriggle chain and perhaps a couple of nudges from persuasion tool of appropriate size should do the trick.
Get a chain break tool (their cheap) and take the chain apart, unwrap it and put it back together - 10 - 15 mins max.
Before you break the chain check for a joining link.
tried again last night & chain wont wriggle free so looks like the chain rings have to come off
Troy, looking at the photo you posted, I think taking the chain ring off is more work than taking the crank off: on a 105 chainring with a wedge crank fitting as in the photo, it is 5 bolts to take of the chainring, vs 1 bolt and the crank extractor, which is less likely to be under as much stress (due to the thread size and the crank dimensions compared with those of the chainring itself) so you're less likely to strip the thread on the crank by using the extractor than you are on the crank when undoing chainring bolts. I disagree that the chain is caught between the rings, it looks to be between the inside ring and the frame.
Just my two cents worth.
You're still most welcome to brink the culprit round and I can fix it quite quickly.
Or not, no biggie.
you would be correct that its caught between the frame & chainring, also left a nice scrape on the frame which i will have to fix