Yes, definitely. I used the d20 Call of Cthulhu critters and spells to very good effect. The "sorcerer" template in that book makes for a very nice (and scary) alternative to the d20 Conan scholar.
Actually, with a few tweaks, the d20 CoC game works as well (or better) than d20 Conan at doing Conan! (it's definitely lighter in terms of rules, it is practically class-less, and the sorcery system is brilliant.)
