They would work in a single channel motherboard, and it wouldn't effect the speed of the actual RAM however it would effect the overall speed because the memory wouldn't be able to send data back and forth as fast as it could in Dual-channel motherboards.
no such thing as dual channel ram.
dual channel refers to a motherboard using two or more Ram slots to take advntage of mutliple ram installation. As the cycle of charge goes up and down, the motherboard utilitzes the particular ram assigned to the charge. In a dual or multi-channel system, the charge is used on both the up and down cycle or somewhere in between. There are multi-channel boards, but they're uncommon.
A dual channel board will have two slots of ram coded to be used in pairs. These slots are usually color-coded. The effect of using dual or multi channel ram is a significant performance gain. rather than use 1 stick for 1 clock cycle, a dual channel board uses 2. so two 512mb sticks would run about 50% faster than 1 gb stick all by itself.
if you are planning on adding ram please visit the guides forum and read the installing ram and upgrading guide.