Using 32 bit ASN numbers

I am doing some research for our company regarding 32 bit ASN numbers. I am trying to locate information about vendor and service provider support. In particular I have not been able to find what Cisco IOS image I would need to load on our router to support 32 bit ASN's. I also want to know what experience people have had with service provider support of 32 bit ASN's -- Brian Raaen Network Engineer braaen@zcorum.com