3GS not camera icon to send MMS

[treeleaf20]

All,
I just purchased the 3GS and I want to send a picture that I have saved on my phone. Apple says it can be done:

apple.com/iphone/how-to/#messages.sending-photos-and-videos

I know the user that I'm trying to send it to has the ability to receive these messages. One is AT&T and the other is Sprint. How can I get this icon to show up?

Thanks in advance.

 

[treeleaf20]

I also just looked at sending a voice note and the option to send it via MMS isn't there either.

 

[shutter]

AT&T has not activated MMS on the iPhone yet. Rumors are it will be out in the next week or so with iPhone OS 3.1