  We report an observation of the weak $6^{1}$S$_{0}$-$6^3$P$_0$ transition in
$^{171,173}$Yb as an important step to establish Yb as a primary candidate for
future optical frequency standards, and to open up a new approach for qubits
using the $^{1}$S$_{0}$ and $^3$P$_0$ states of Yb atoms in an optical lattice.
