How to Unlock Iphone 3G

Are you trying to unlock or jailbreak?

Basically, What carrier do you plan on using?

I want to do both.I want to use on different network and want to install some sftwares

Here is a step by step guide taken directly from Engadget on how they unlocked their iPhone along with a video of them actually doing it.

VIDEO LINK HERE

Ok, here it is, the first time on camera you've seen a real iPhone software SIM unlocked from start to finish (and not done with the demo app iPhoneSIMfree sent out last week). The last iPhoneSIMfree unlock video we had only showed of the end result of a successful iPhone unlock, which took place off-camera. This time we're doing the entire process, which we confirmed earlier this morning, on video. For quick reference, here are the steps we took on camera:

1. Started with AT&T SIM inserted
2. Inserted T-Mobile SIM, showed that it produces invalid SIM error (expected behavior for a locked iPhone)
   
3. Connected to iPhone over SSH
4. Transferred iPhoneSIMfree unlock app over SCP
5. Restarted SpringBoard (iPhone default application launcher)
6. Ran iPhoneSIMfree app
7. When complete, iPhone shows that T-Mobile SIM no longer produces invalid SIM error, instead asks for activation (expected behavior for an iPhone that has a valid SIM, but is not yet activated)
   
• Prep for re-activation off camera using iAsign (phone is now unlocked, but still activated with AT&T)
8. Back on camera: activate iPhone with T-Mobile SIM using iAsign
9. Make test call to another phone
10. Activate iPhone once more with AT&T SIM using iAsign

Granted, we don't expect end-users to take all these steps when unlocking their iPhone -- we just went a little overboard here so everyone can see the release software is functional, and unlocks iPhones as advertised. Embedded player after the break.

ya i know.You can unlock your iphone using Remote unlocking method.It's the best way to unlock your mobile.If you are interested in this method visit unlock-zone.com Here you can unlock your mobile without jailbreaking.