So a few months ago I got my families phones switched over to ting from sprint. Basically just followed the guides on going from sprint to boost, except using a ting phone instead of a boost phone. Since there has already been solid information out there, I'm just going to point you to the guides I used.
I followed the Epic 4g Boost Mobile Guide, since the SGS2 is pretty similar. I bought the Kyrocera phone that ting was carrying to copy the settings from. I had to call Ting (they were awesome) and get the SPC code for the Kyrocera so I could read the setting off of it.
Just follow the two guides below and watch the video. (You will also need the programs mentioned, use google)