You can win cash by playing a game on the iPhone!!!

Guess and Win 2010 is a simple, yet addictive, guessing game with a cash prize for the top score at the end of the year. The prize ranges from $100-$20,000 depending on sales. Visit www.manyappolis.com for details. This contest is not sponsored by Apple.

When the game begins, the app randomly generates a number within a given range. You then see how many attempts it takes you to guess the number. If you get it on your first attempt, you advance to the next level, where the range of possible numbers is greater.

Compete with your friends via Twitter and Facebook. When you advance a level or beat your best score, you are given the option to post your new score to Twitter or Facebook to challenge your friends.

You can also compete worldwide. You can post your score to the leader board to see how you compare with the other players. Whoever sits at the top of the leader board at the end of the year will win the cash prize.