I believe the original was by Italian designer Roberto Barazzuol, and the new one (which they've stopped using) by New York agency Laird & Partners.

Ah brilliant, thanks.

Didn't they 'use' the failed logo for 1 week or something like that?

Yes, they scrapped the new logo, made another mistake by trying to crowdsource a replacement logo, and eventually just reverted back to their old logo.

There was a discussion on Typophile about it (http://www.typophile.com/node/74956), and if you Google you'll find articles about it at several sites.

Wow, I had never seen that before. I'm surprised that even got past the concept stage. It looks like the designer just set the word "Gap" in Helvetica, made a few tweaks added a square and said, "Nailed it!"