If you have recently upgraded your iphone 3G to OS 3.0 and you live in Pakistan then here are the steps to follow to get most our of your iPhone:
1. Jailbreak your phone by using RedSn0w and then unlock your iphone using Ultrasn0w Software from DevTeam. Apple has not launched iphone in Pakistan so we don't have any other option...Sorry Apple!
2. Turn on your MMS & tethering. To turn on Tethering visit
here and select custom carrier, I use waridTel, so APN is warid. Yours differ. Check your mail from iphone and download the file which is send by the site and click install. You will then see Tethering option available in Settings->General->Network
3. To enable MMS simple put the MMS settings (as shown in the pic.) in Settings->General->Network->Cellular Data Network.

4. Caller ID Fix, You will notice that some of SMS does not have names, To fix this go into the Cydia and download CallerID and Format (iSpazio) Fix for OS 3.0.
5. More Later.......