Does anyone know if there is a free untethered jailbreak for iPhone4 running 6.1 without the use of a computer
There isn't yet, as Cody said, except for with computer. Don't use it yet though, as it is not fully functional. I have tried it, and it freezes a lot. Wait until there are more options out there.
Not yet, but soon there will be many options. The only one currently for 6.1 is with a computer and is called evasi0n