Decrypt keychain passwords using the security command?

So I find I'm one of the 6.5 million people whose LinkedIn passwords were recently grabbed by thieves (confirmed by LinkedIn). That password was used on a number of other websites, so I clearly need to run around and change a bunch of passwords.

I have a ton of Internet passwords stored in my keychain though, so working my way through them one-by-one will take forever: double-click an entry, click Show Password, enter my login password, lather, rinse repeat. For some reason, there are several records stored for the same website.

So, is there some way I can run the security command, give it my login password once, then have it display the unencrypted Internet passwords? I played around with it a bit a couple days ago, but never got it to work as I wanted. I'm on Leopard, but also have a Lion system available (assuming the Leopard keychain file can be grokked by the Lion keychain tools). Anything which will lessen the effort necessary to identify all my sites which use the bad password.

Thanks,

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