Yeah, that's a pretty dumb question alright.
I am KIDDING!
Let's be clear about the difference between Dual Processors and Dual-Core Processors. Dual Processors means you actually have two separate physical processors in two different sockets on the same motherboard. Something like this: dual cpu mobo help needed - Vista Forums
In that case, each CPU would run at 2.2GHz and you would have twice that in processing power.
Dual-Core means there are two separate CPU cores on one die (one physical processor). This gets a little trickier to explain, as there are many different ways of putting this together. In some cases, the CPU cache is shared between cores. In others, each core gets its own. There are also different ways that the individual cores can communicate with each other, or maybe not communicate at all with their fellow core(s). Multi-core processors are rated at the speed of an individual core, so you can't just add them all together and call that your "CPU speed".
How useful these are depends somewhat on the software they are running. If the software runs a lot of parallel processes (two or more going on at the same time), then multi-core CPU's are great. If the processes are serial (one after the other), then the spare core(s) don't have much to do.
You can read a little more here: Multi-core processor - Wikipedia, the free encyclopedia