Taken from the defunct HTML 3 spec.
Char Entity Tex Name PS-Symbol Math-8 α α \alpha alpha 61 61 β β \beta beta 62 62 γ γ \gamma gamma 67 63 δ δ \delta delta 64 64 ε ε \epsilon epsilon -- 65 &vepsilon; &vepsilon; \varepsilon var epsilon 65 3B ζ ζ \zeta zeta 7A 66 η η \eta eta 68 67 θ θ \theta theta 71 68 &vtheta; &vtheta; \vartheta var theta -- 79 ι ι \iota iota 69 69 κ κ \kappa kappa 6B 6A λ λ \lambda lambda 6C 6B μ μ \mu mu 6D 6C ν ν \nu nu 6E 6D ξ ξ \xi xi 78 6E ο ο .... omicron 6F 6F π π \pi pi 70 70 ϖ ϖ \varpi var pi 76 7B ρ ρ \rho rho 72 71 ϱ ϱ \varrho var rho -- -- σ σ \sigma sigma 73 72 &vsigma; &vsigma; \varsigma var sigma 56 5B τ τ \tau tau 74 73 υ υ \upsilon upsilon 75 74 φ φ \phi phi 66 75 ϕ ϕ \varphi var phi 6A 7A χ χ \chi chi 63 76 ψ ψ \psi psi 79 77 ω ω \omega omega 77 78See also the same information as a table (slow in Grail!).