I was on www.trails-online.com, watching the quicktime files hoping to learn something, and I always see then balancing up on the back wheel without movement. How do I do this? Are there any balancing techniques?
What you are refering to is called a lurch or a real wheel bounce.
Its a fairly basic technique but is the fundamental skill to get anywhere in trials.
what they are actaully doin is when they they have there bike up on the rear wheel they are at the ideal angle (ie balancing point with the brake on)
They then let the bike fall slitely forward ( but then counter act that with around a quarter kick of the pedals to bring it back to the balancing point).
It is possible to do this on the spot with a little help from the wrists and upper arms which adds the small hop.
After practice this allowes for lurching forward or turing all, on the rear wheel.
Finding your balancing point on the bike is probably the hardest part of learning to lurch and then the combination of controlling the rear brake and pedal kick to retain your postion on the rear wheel. But once mastered this leads on to everything in trials
As you are using a FS bike if you were to try anything like that its best to lock up both your shocks as much as possible or idealy use a hardtail.
This is extremely breif and probably wont make any sence but there should be a better description on bike-trials.com