Using Mobile Phone Spyware with Unjailbroken iPhone 4s?

The phone I wish to view is an iPhone 4s, while I own an iPhone 4. Neither of ours are Jailbroken.
I became aware that in order to use Mobile Spy the phone had to be jailbroken.
I was seeing if there was another software that could be used that doesn't require me to jailbreak either of our phones.
and if not, who's needs to be jailbroken? Mine or theirs?

P.S. We both have the ios 6 update

Ok first thing first Mobile Spy Software only work in a jailbreak iPhone. Mobile Spy is Offering the best iPhone 4s Monitoring Software it is reasonable in price and best in working according to current rating. For user reviews you can check at
http://www.cellphonespyware.us
I don't think so IOS 6 is Supported because IOS 6 is iPhone 5 OS not of iPhone 4s and iphone 5 jailbreak is not available anywhere in the market till now.

I'm afraid you have to jailbreak your target phone (iPhone 4s) before installing any spyware on it. And most trustworthy monitoring programs need to be physically installed on the target device.
http://www.spy-mobile-phone.com/