The following are the steps to get your caller id back into working condition if you just pwned your iPhone to the latest 2.0 FW. This was also called the AppSupport Patch… Well actually its still called the same, only Apple modified the way they were doing it and the location.
CAUTION: If you do not know what OpenSSH, WinSCP are, then you should stop right now.
Step 1: Install OpenSSH from Cydia (found easily in featured apps)
Step 2: Restart iPhone
Step 3: Use winscp to connect to the iPhone via your IP address Username:root Password: alpine
Step 4: Download this file
RapidShare: Easy Filehosting and extract it to your desktop
Step 5: Navigate to the following folders on your iPhone using WinSCP or FUGU and replace the following files:
/System/Library/PrivateFrameworks/AppSupport.framework/PhoneNumberTemplates.plist
/System/Library/Frameworks/UIKit.framework/PhoneFormats/UIPhoneFormats.plist
with files from ZIP
Step 6: Restart iPhone
Step 7: Enjoy!