  Poisson Voronoi diagrams are useful for modeling and describing various
natural patterns and for generating random lattices. Although this particular
space tessellation is intensively studied by mathematicians, in two- and three
dimensional spaces there is no exact result known for the size-distribution of
Voronoi cells. Motivated by the simple form of the distribution function in the
one-dimensional case, a simple and compact analytical formula is proposed for
approximating the Voronoi cell's size distribution function in the practically
important two- and three dimensional cases as well. Denoting the dimensionality
of the space by d (d=1,2,3) the $f(y)=Const*y^{(3d-1)/2}exp(-(3d+1)y/2)$
compact form is suggested for the normalized cell-size distribution function.
By using large-scale computer simulations the validity of the proposed
distribution function is studied and critically discussed.
