Just joined, I've been interested in the sport ever since I started riding bike trials six years ago.

I think parkour is one of the best ways to cross train with other sports and thought it would be a great activity for winter as the riding becomes limited in this area.

Yes   I watched those videos number of times as well as other roll technique tutorial.  I'm only practicing on grass & at home with mats at the moment but did few rolls from small 2' obstacle onto a grass without hitting top of the shoulder or landing straight/onto spine.

Right now my focus is to be more flexible and do basic lines.  A lot of lines I'll have no problems doing on the bike but is also helping me with practice more precise balance and bailing/landing properly.  I think it's also a great cross training sport as it makes running and jogging a bit more fun adding basic moves

and if you want to work on balance id suggest cat balance

http://www.youtube.com/watch?v=JjVW_S4sZbY

as a nice exercise that deals with balance, pistols are great (plus they work your legs)
http://www.youtube.com/watch?v=_pagSm57Mqw

i didnt watch the full video but if this guy doesnt explain it, you can put your hands out to your sides or in front of you, wherever you feel most comfortable

I used to do a lot of the pistol squats, haven't done them in awhile & now that I'm not so flexible I really need to work on that!

Errr cat balance I rarely do skinny objects on my bike either but guess I really have to practice them now