free running or parkour is where u get people running around jumping off things or over rails and shit
YouTube - parkour
"tricking" is all about martial arts tricks or trickz, its all based on aerial techniques, kick flips etc
YouTube - Trickz
although as time goes on they are becoming merged, you still get people who only trick and people who only free run but you are getting more and more hybrids kind of blurring the line a little
unfortunately you also get many people who suck at both who think theyre great
aye thatd be pretty cool man