Lump Jockey,
As far as I'm aware (I'm sure one of the real airline pilots will correct me if I'm wrong) there's usually a specific speed below which the tiller is used, both on take-off and landing.
As for the ailerons, there are a couple of times that you might use them on the ground. In general, the bigger the aircraft, the less important they are.
During the take-off and landing roll, you would use into-wind aileron. This is to prevent the wind blowing you sideways off the runway, or from lifting a wing - it's not realy "steering" as such.
While taxying, you should (but most pilots don't), on most aircraft, use into-wind aileron when taxying with a headwind, and out-of-wind aileron when taxying with a tailwind. Again, nothing to do with steering - this is to prevent the wind from lifting the into-wind wing. Obviously on a 747 there is very little chance of the wind doing that! But on a little single-seater aircraft it's a real possibility with any kind of wind.
It's also possible to use adverse yaw of ailerons to assist with steering. (Do you know what adverse yaw is? If not, just say, and I'll post again to explain, unless someone beats me to it.) You would use the ailerons in the opposite direction to the way you're turning - left aileron for a right turn. Adverse yaw always works in the opposite direction to the way you've moved the ailerons.
Almost all modern aircraft have sufficient control, using nose-wheel or tail-wheel steering and differential braking, that it would be very unusual to see this method used! But there are a small number of older designs out there, with no brakes and just a tail-skid at the back, that have no real method of steering except using aerodynamic controls (or, more commonly, a man standing by the wing helping it around the corner!) If you're turning a tight corner in this type of aircraft, then adverse yaw might be useful. Bear in mind, though, that you'd need a reasonable amount of speed for the adverse yaw to have any effect. In fact, you'd need a reasonable amount of speed for the rudder to have any effect too, but less so. If you find yourself having to resort to this, then unless you're very experienced in that type of aircraft, you'd be better off shutting down, getting out and pushing! But it does make a nice demonstration, even if it has little practical value.
FFF
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