I'd be interested. Verifying your vote will require either something you know or something you have, I would think. Either of which could be used by a malicious third party.
Look up zero knowledge proofs http://en.wikipedia.org/wiki/Zero-knowledge_proof
You'll have to go into it a little more given that the statement in question would look like "I, Richy_T voted for Satoshi Nakamoto(B)". That's the information that would need to be verified and the information that the third party would want.
Unless you're talking about knowing that the vote is correct without needing the individual voters to be able to verify their votes. Which is a different issue.