This one is pretty good. I read it through, and it is not the exact one that I have used, but it is close enough. Please read my pointers below, in addition to the tutorial.
1) this is 99% mental, I cant tell you how many times i ran up and started to to it, but bailed right before flipping and just landed on my feet. finally, me and my friend came up with a little saying that we still use to this day. . . JFDI. (Just F&#king do it). That is the mentality to have, and when i finally let go and went for it, i nailed it from the on.
2) make sure the wall your doing it on is sturdy, ive kicked holes in 2 walls, and have been half buried in a third because i started to do a wallflip without testing the wall first, lol.
3) I reccomend placing your foot slightly above chest level on the wall. After much experimenting, i found that the best placement. Consider that you want your leg to be at a 90* angle to the wall and also to your body (you, your leg, and the wall should make an "H").
4) as soon as your foot lands on the wall, LOOK BACK. I had a friend standing about 10 feet away from the wall, and my goal each time was to be able to make eye contact with him. If you dont throw your head back, you will NOT flip.
5) I reccomend a hard, unpadded wall, and a crash mat underneath you on the floor to learn. i found that padding the wall took away some of the momentum, and when i went from a padded wall to a non-padded wall, i felt like i was relearning how to do it.
6) as soon as your foot is on the wall (whichever leg you feel comfortable with, i use my left), and your head is looking behind you, your other leg (for me, that would be my right) pushes off the ground slightly, as if i were going to continue running vertical up the wall. That leg does NOT touch the wall at all, instead, it is the force that propells your flip. Swing that leg as if you were punting a football. After practice, I found that the force of that leg alone is enough to power my flip, and take me away from the wall. I would reccomend that while learning, the leg that is on the wall (for me, my left) should push off just a bit to assist the flip.
Things to remember:
1) JFDI! again, this is 99% mental, you have to just let go and do it.
2) get a crashmat underneath you. .safety first.
3) if you follow this, and remember my tips, you WILL NOT hit your head on the wall, this is a common fear. In my years of doing this move, i hit my head on the wall once, and it was because my right toe hit my left heal while i was in the "kicking" motion, and halted my momentum mid-flip. It didnt hurt that bad at all thought, haha.
4) having a friend there to learn it with you is a very good thing. Its nice to have someone to talk to and discuss the finer points of the move, and it also adds some encouragement. I found that me and my friends were cheering for each other, and it really helped get it done.
5) I cannot emphasize enough the fact that you will not be able to do it if you cannot let go of the fear, and JFDI. this is one of the easiest moves I know, and after i got it down, I have not falled/messed up once. The only way to get hurt doing this is to be up tight and scared to commit.
I hope this helps, feel free to post here if you need any more tips, or have any questions. I had a video of me doing it off a friend of mine's chest, but I can't find it, ill post it if I do. By the way, the chest wallfip is amazing, and can definatley get a crowd reaction, haha.
I also reccomend having an "enemy" be chasing you, and both of you run at a wall, you wallflip over him, land behind him, he runs face first into the wall, you grab him from behind and roll backwards while loading him on one or both feet, and throwing him using your momentum. That was a very nice use of this move taht we have done in 1 of our movies. It turned out very nice. (I believe that Liu Kang does something to that effect in his fight with Sub-Zero in the original Mortal Kombat movie, just so you can get an idea)
good luck and enjoy!