Double sided is much better for circuits with high speed logic or low noise requirements. It is easy to use a double sided pcb. If you are making your own boards and will use leaded components (ie. DIP etc) then etch your single sided pattern on one side as you normally would, but cover the entire other side with something to resist the etchant, like for example I use masking tape and make sure its stuck down really good.
Once you have etched your board and cleaned it up, you remove the tape from your "ground plane side". I hope you understand that the ground plane side is also your component side for leaded components.
Next, you drill your holes as you normally would for the components. Now the only problem you have is that component leads will short to the ground plane on the top side. We fix that by taking a large drill bit, like a 3/8 or similar standard twist bit, or a countersinking bit if you have one. Any bit with a broad shallow tip angle. Then you carefully countersink the component side of each hole that you don't want shorted to the ground plane. What you should end up with is a tiny ring of bare fibreglass board cleared of all its copper around where the lead goes through the hole. This ring only needs to be tiny, like .01 or .02 inches, just enough to insure that ground plane copper doesn't touch the lead. And you don't cut it very deep, that's the purpose of choosing a drill bit with a shallow bit angle at the tip, so that it cuts a ring of copper without actually drilling through the board. You don't want to drill through the board and enlarge the hole that appears on the solder side.
This would be easier with a photo, anybody got one?
Once you have finished countersinking all the holes that are not for grounded leads, you solder your components down on the solder side as usual, and any leads that are grounded get soldered on both sides of the board so that the ground plane is connected to your solder-side circuit ground.
its easy really.