link
Actually, I heard it on the news that it was a positive confirmation. Also I heard General Kimmett's announcement.
So, I had to go find a link for you. Here is one from the DOD.
It doesn't give specifics about the testing but it does say that it is sarin.
The Pentagon reports with Bret Baier also confirmed it.
http://www.defenselink.mil/news/May2004/n05172004_200405174.html