MacRumors.com

A Macintouch.com reader and MacBidouille notes that Apple has adopted a Sony drive for their Superdrive on the new iMac. From Macintouch:

I just purchased a new 1.0 GHz iMac from an Apple store yesterday. To my surprise the Apple System Profiler reported that the DVD drive was not a Pioneer drive, but instead is a Sony DVD RW DW-U10A. Apparently this is a DVD-R, DVD-RW, DVD+R, and DVD+RW drive. I had not been aware that Apple changed DVD drive hardware venders.

Apple has previously used a Pioneer drive in the past (for their "Superdrive"), which was limited to DVD-R and DVD-RW formats.

This MacRumors.com thread discusses the switch and confirms that the new iMacs use a Sony drive.

Addendum: Some users report that their new iMacs still use the Pioneer drives, so it does not appear to be implemented across the line.