It is hard for me to find a site/book/article explaining how, exactly, tau particles are created.
Tauons are leptons like the electron and the muon, only heavier. They weigh in at 1776.86MeV according to the Particle Data Group (cf http://pdg.lbl.gov).
They can be produced in a particle accelerator directly via particle + anti-particle annihilation - as long as the total energy in the center of mass system is $> 2\cdot 1776.86MeV$. For example $e^+ + e^- \rightarrow \tau^+ + \tau^-$.
An alternate pathway is when the particle + anti-particle annihilation produces a pair of heavy quarks (b or t) and at least one member of the pair decays via the weak decay into a $\tau$, $\tau$-neutrino plus other particles.
The tau lepton is a very short-lived particle with a mean life time of only 0.29ps. So, it is in practice only detected by recording its decay products and reconstructing (ie computing) its mass from those.
For more details look at http://www.thefullwiki.org/Lepton