This is a short summary of a neighbour thread:

Quote from: https://bitcointalk.org/index.php?topic=152363.msg1619287#msg1619287

Whole thread:  https://bitcointalk.org/index.php?topic=152363.0

"this wasn't a double spend - it was a single spend on two different blockchains - I'm not sure why everyone is so concerned about this - the spend only existed once in the longest chain, it just happened that the longest chain changed, and it changed after 6+ confirmations had already happened in a previous longest chain.  The issue here was that the merchant ignored or did not know about the advice to not accept confirmed blocks from the currently longest chain (the 0. because the 0.7 chain was going to outgrow it and invalidate those transactions.

At no point was there a double spend in the longest chain, which is exactly how bitcoin is designed to work.

Will"

So stop the "double spend panic" ... Nothing near a 2-spend happened really.