How to jailbreak iPhone 4s?

Hi!

I don't remember what software I used to jailbreak my iPhone 4s. I jailbreak it long time ago the moment they released it. I jailbreak it on version 5.0, but it's getting out of date and I don't even have 4G network.

So what is the latest version I can upgrade and still jailbreak on my iPhone 4s?
Can I have links, instruction, etc?
Thanks!

P.S. What about iPad2? I wish to jailbreak that too to get Cydia.
Thanks!