AppSync 4.0 Updated For iOS 4
Now that iOS 4 is out, and also a jailbreak for iPhone 3G on iOS 4 became available (redsn0w 0.9.5 beta), the next step is to get some great Cydia apps updated for this latest iPhone OS. AppSync, the popular Cydia app that lets you install cracked apps and games (ones without DRM) on your iPhone.
AppSync 4.0, the updated version added support for iOS 4. Like previous versions, it allows you to install .ipa files manually on your iPhone without the need for iTunes by patching the MobileInstallation file. Here is how you can install AppSync on your jailbroken iPhone.
1. Jailbreak iOS 4 on iPhone or iPod Touch.
2. Launch Cydia, and navigate to Manage –> Sources –> Edit.
3. Then touch ‘Add’ and enter the source http://cydia.hackulo.us/ as Cydia/APT URL.

4. Touch ‘Add Source’ and let Cydia automatically update your sources.
5. After the updation is done, search for ‘AppSync for iOS 4.0’ in Cydia and install this application.

That’s it. You can now install cracked games on your iPhone or iPod Touch by simply downloading the .ipa file and syncing it with your device using iTunes. The installation is started as soon as the syncing is started.
LOL. I knew there was SOMETHING I forgot to do when I upgraded. Spent several hours trying to get my apps back. Thanks so much for this guide!
Nice job!!!Keep up the good work..