There's a lot of very good resources on Instructables for doing laser printer toner transfer, and for complicated circuits or fine-pitch work it's probably the way to go.
But what if you're stranded on a desert island with no laser printer and you still want to work out a super-quick printed circuit? What then?
(OK, honestly, I just find it a bit of a hassle to fire up Eagle, etc just to make a quick and dirty battery-charger circuit.)
Here's a start-to-finish home-etching-with-Sharpies mini-tutorial. It's basically "draw the circuit with sharpies, then etch" but the gold is in the details.
Step 1: Stuff You'll Need
From blank copper-clad board to working prototype:
Copper clad board
Ruler and matte knife to cut it
Scrubby pad to shine it
Three (3!) Kinds of Sharpie: Ultra-Fine, Fine (Regular), Chisel-Tip (Wide)
An empty piece of protoboard (the secret ingredient)
Drill and bit
Pen and paper for working out the circuit layout