How much time have you got?
It is a complete minefield with what seems like something new popping up every day. Like most New Age spiritual practices there's always someone willing to take your money.
Before you jump into the internet research, consider your motives. What kind of healing do you want to do, how do you want to do it, what's in it for you (spiritually of course!) Are you mentally and spiritually strong enough? What are your strong and weak points? Its like buying a hat, get one that fits properly!
Personally I'm not a fan of Reiki, it became very much the "in thing," and if you had the money, you could become a Master in as short as 3 months, that dosnt sit right with me but having said that, Ive never tried it, just not my thing.
No modality is worth anything unless its effectiveness is provable so finding out about people who have had work done on them would be a good place to start. I'm sure you will find the one thats right for you