No hacks for the game that I know of... there is a cheat code to unlock all songs but its only for playing them as you can't save progess with the cheat.
1. Turn on your gaming system, making sure the Rock Band game is in and your instruments are connected. Wait for the startup screen to finish or bypass it by pressing any button on your instrument or controller.
2. Enter the cheat code from any instrument--although it's easier with the drumset or guitar--to unlock all Rock Band songs. Press in this order: Red, Yellow, Blue, Red, Red, Blue, Blue, Red, Yellow, Blue.
3. Notice the screen that pops up and tells you that you correctly unlocked all songs. If you didn't get this screen, you probably need to enter the code quicker or try another instrument.
4. Press the green button to accept the cheat code and play all available songs on solo quickplay or band quickplay. This cheat disables saving, so you won't be able to save your progress and must enter the code every time you start the game.
New songs must be paid for and downloaded.
This post has been edited by Havok: Apr 26 2008, 02:23 AM