Here are the instructions from another this site:
http://ipodtouched.net/?p=307
How to guide:
1. You need to be on jailbroken 2.0 with Cydia installed. (If on a Mac use PwnageTool and if on Windows use WinPwn)
2. Now install OpenSSH. Click on Cydia and then click Install(Sections)>Networking>OpenSSH then click Install>Confirm (if you get a running out of disk space error click ok) Then click close window. Now click on the home button.
3. Now log into WinSCP (if you dont know how watch this) The first time you try to login you may get a connection timeout error, click retry and it should work. If you still get an error reboot your iPod/iPhone and try again.
4. Create a folder called Documents in /var/mobile/ and set permission to 777
5. Create a folder called Documents in the /Applications folder and set permissions to 777. This will fix the Disk Full error message seen when launching the game.
Note: You will only need to create these two Documents folders once
6. Now go to <root> /System/Library/PrivateFrameworks/MobileInstallation.framework
7. Rename the file MobileInstallation to MobileInstallation.bak
8. Download this patched file - HERE
9. Place the patched file into the /System/Library/PrivateFrameworks/MobileInstallation.framework folder and set the permissions 775 for the patched MobileInstallation file
10. Reboot your iPhone/iPod Touch- IMPORTANT!
11. Download cracked Games and Apps from Update: below scroll down
12. Download at least one App fromt he App Store(Free or Paid) IMPORTANT: Otherwise you will get an error! [Only need to do this once]
13. Double click on the cracked .ipa you downloaded
14. Sync your iPhone/iPod Touch and enjoy!
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http://ipodtouched.net/?p=307