Is iOS 7 available on an iPhone 4S?

I have just seen that iOS 7 is out and was wondering whether it's available for the iPhone 4S and if so, when?

It is NOT out, it has just been announced and is running BETA tests at the moment.

Hello there the 4S will get the new software as it is still pretty new and will get this update and to be honest will probably get the next version also.
As for when it will be released well you guess is as good as anyones! I would suggest a couple of weeks before the new iphone, So a decent guess would be around september/october.

YEP. In about three months.
http://www.apple.com/.../features/
(iPhone 4 and 4S compatible - on bottom of page.)

It will be in 3 months

You can download IOS 7 Beta for all devices here: http://sourcecheat.com/ios-7-beta-download-free-install-links-how-to/

IOS 7 has not been released yet, but it will be compatible for iPhone 4S. It is coming out in the fall.
iOS 7 will also be compatible with:
iPhone 4
iPhone 4S
iPhone 5
iPod Touch
iPad 2
iPad w/ retina display
iPad mini

You're welcome.