Hold down the "Alt" button on your keyboard , and while holding it down, press the number 3 on the number pad on your keyboard.  When you release the "Alt" button the ♥ will appear.
Have fun!    ♥♥♥♥

OR ... Open the "Character Map" on your computer. (e.g. In Windows XP, it's under Start/All programs/Accessories/System Tools/Character Map)  HEAPS to play with in there!  ☺☻☼♀♂♣♥♦♫♪ just a few of thousands

☺