  In this paper we discuss the question of whether the entropy of cosmological
horizon in some asymptotically de Sitter spaces can be described by the
Cardy-Verlinde formula, which is supposed to be an entropy formula of conformal
field theory in any dimension. For the Schwarzschild-de Sitter solution,
although the gravitational mass is always negative (in the sense of the
prescription in hep-th/0110108 to calculate the conserved charges of
asymptotically de Sitter spaces), we find that indeed the entropy of
cosmological horizon can be given by using naively the Cardy-Verlinde formula.
The entropy of pure de Sitter spaces can also be expressed by the
Cardy-Verlinde formula. For the topological de Sitter solutions, which have a
cosmological horizon and a naked singularity, the Cardy-Verlinde formula also
works well. Our result is in favour of the dS/CFT correspondence.
