I'm my opinion the best way to memorize the notes on the fretboard is to simply draw 6 equally spaced lines long on a piece of paper. These reperesent the strings. Then draw 12 frets acroos the long lines. You can do this in microsoft paint so you can print as many as you like. I put several "fretbalrds" on a singe sheet.

Then start writing the names of the notes. Try and skip around randomly. Mix it up and befroe you know it, you'll know it :D