iTunes credit good for books?

Can an existing iTunes credit be used for purchasing books through the iPad iBooks store?

That's a great question - bump because I'd love to know the answer as well.

Haven't tried it myself, but I did notice a redemption section in the ibooks store.

To answer my own question, YES it does.
When in the iBook store the amount showe up at the top just like it does in iTunes.

Yes iTunes card Covers all areas in iTunes

Thanks for the answers! Good to know!