  We present the results of a complete tree level calculation of the processes
pp(\bar p) -> Wb\bar b and Wb\bar b + jet that includes the single top signal
and all irreducible backgrounds simultaneously. In order to probe the structure
of the Wtb coupling with the highest possible accuracy and to look for possible
deviations from standard model predictions, we identify sensitive observables
and propose an optimal set of cuts which minimizes the background compared to
the signal. At the LHC, the single top and the single anti-top rates are
different and the corresponding asymmetry yields additional information. The
analysis shows that the sensitivity for anomalous couplings will be improved at
the LHC by a factor of 2--3 compared to the expectations for the first
measurements at the upgraded Tevatron. Still, the bounds on anomalous couplings
obtained at hadron colliders will remain 2--8 times larger than those from high
energy gamma-e colliders, which will, however, not be available for some time.
All basic calculations have been carried out using the computer package
CompHEP. The known NLO corrections to the single top rate have been taken into
account.
