Once you reach a set level you'll receive a message telling you what new tool you've earned.
There is a hidden password system in Mysims to unlock unique outfits and special furniture. To reach this password screen, do the following.
-While running around town, bring up the pause screen with the - button. Then input the following commands on the Wiimote (not nunchaku):
2 button, 1 button, Dpad down, Dpad up, Dpad down, Dpad up, Dpad left, Dpade left, Dpad right, Dpad right.
A special keyboard to enter passwords will now appear allowing you to unlock clothes and furniture. The following 3 passwords are a gift for reserving the game, and are case sensitive!