Yes, despite the iPhone headphones not being listed as an iPad accessory on Apple's web site, the iPhone headphones are fully compatible with the iPad.
This means that not only are the headphones suitable for listening to stereo audio through the iPad, all of the buttons and click-features of the iPhone headphones are understood by the iPad. This includes:
- click to play/pause a song
- double click to skip to the next song
- triple click to go back to the previous song
- volume up and volume down buttons
The microphone on the iPhone headphones also works with the iPad.