We need a debt rating service rating service

Very meta. Who rates the rating services?

I saw this in the Wall Street Journal, an article today called Stocks Wind Down a Brutal May:

"Trading was especially volatile in the afternoon after Fitch Ratings lowered its rating on Spain's debt to AA+ from AAA, but said the country's outlook is stable. The downgrade came despite this week's passage of austerity measures by the Spanish government—a move that bulls had hoped would help the country avoid struggles similar to those of Greece." (from The Wall Street Journal)

And I thought, who is this Fitch Ratings Service, and can we trust them? Hmm. Who can I ask? I need a Dept Rating Service Rating Service.