I've been having a look round and for the life of me, can't get the iFrame to show it's face. Can you PM me a specific URL it's known to appear at please?
In the meantime, you can identify the file(s) or databases containing the malicious code itself, by searching for "eval", "document." and "script" (that's by no means all of them, but should be enough for a good start, and it's obviously worth noting that script will be everywhere if the site uses Javascript).