Conroe for the most part is dual-core, hence it's offical name: Core 2 Duo. However, there will be low-cost single-core Conroe based processors labled as: Core 2 Solo.
lhuser, Conroe is only dual-core and single-core. However, the Kentsfield core will be quad-core. It is essentially two Conroe based Core 2 Duo processors on one die.