I forgot my passcode to unlock my iphone what do i do?

It depends on the severity and the settings you have given the iPhone and whether you have the computer that you synced your iPhone with... Here's the full explanation. I would recommend reading the second paragraph first, but the solution if you really forgot your password is in the first paragraph. 
==If you have the computer you synced your iPhone with==
If you cannot remember the passcode, you will need to restore your device on the computer that was used to originally sync the iPhone or iPod touch so that you can reset your passcode and resync the data from the device (or restore from a backup). If you restore on a different computer that was never synced to the iPhone or iPod touch, you will be able to unlock the device for use and remove the passcode but your data will not be present. Refer to "Updating and restoring iPhone and iPod touch software."

"If you enter the wrong passcode too many times, you'll see a message that says "iPhone is disabled" and to try again later. If you repeatedly enter the wrong passcode, iPhone or iPod touch will be disabled for longer intervals, before you can try again. After too many unsuccessful attempts, you won't be able to try again until you connect to the computer you normally sync with. Note that starting with iPhone 2.1 software, there is a setting to cause the device to erase itself after 10 consecutive incorrect password attempts. This setting is off by default. It  can be turned on by tapping Settings > General > Passcode Lock after you enter a correct passcode." 
The full article can be found here: http://support.apple.com/kb/HT1212
==If you don't have the computer you synced your iPhone with==
If you don't have the original computer the iPhone synced with, the only solution is to force your iPod Touch into recovery mode and then restore it. You will lost all the data on the iPod Touch, but after this method is done, everything will work. You can find the steps to solving this problem here: 
http://support.apple.com/kb/HT1808?viewlocale=en_US

I found this iphone and it has a passcode and it say to hook it up to itunes but when i do it says thias iphone has a passcode try again? what do i do

There is a very easy and simple solution for this.
Simply put your phone in DFU mode (check youtube or google on how to do that) and when iTunes will show you that your phone needs to be restored and updated so you click OK. As easy as that, no passcodes or anything.

Hi i have a i phone 3g ive forgot the passcode, when i huk it up onto i tunes, too restore it , it says it cannot let me do anything due to a passcode???? which is the best way to remove the passscode?

thanks

If you cannot remember the passcode , you will need to restore your device on the computer that was used to originally sync the iPhone or iPod touch so that you can reset your passcode and resync the data from the device (or restore from a backup).Ifyou restore on a different computer that was never synced to theiPhoneor iPod touch, you will be able to unlock the device for use andremovethe passcode but your data will not be present. Refer to Updating and restoring iPhone and iPod touch softwarehttp://support.apple.com/kb/HT1212

I bought this iPhone off a friend for my daughter, it was jailbreak but some how my daughter has put a password on to lock and she's don't no the password, iv tried it so many times now the apple sign is staying on the screen it won't turn off. Wat can I do to solve the problem?

Iforgot my passcode to unlock my iphone 3g

Just connect your iPhone to your computer that you normally sync with, do a sync with iTunes, and it will reset the number of attempts you are allowed. So it gives you 10 more tries. If you still can't remember, just do a sync again.

Restore on a different computer that was never synced to the iPhone or iPod touch

Does anybody have the solution to this problem. I need some help too.

If you forgot iPhone passcode, you will need to restore your phone via iTunes.
Firstly you have to put your phone into the restore mode.
Plug your iPhone into your PC or Mac with the USB cable
Press and hold the power button at the top and then slide to power off the iPhone
Press the power button to power the iPhone on and keep it held while simultaneously pressing the home button
After a few seconds a yellow alert triangle will appear and the iPhone will say it is iPhone Restore Mode.
Open up iTunes and click on the Summary tab
Click on Restore to restore your iPhone. This will reset all your iPhone's setting to the factory defaults, including the Passcode. You should then follow the steps above to activate the Passcode with a memorable number and un-lock it.
Forgot iPhone Passcode How to Unlock iPhone Passcode

My iphone have been disabbled. Its a 3gs and i was running on ipad baseband which i can not restore with itunes. When i connect to itunes, it tells me to unlock my phone before it can synchronize. It was working well before this code error came in.
I read on the internet that i should delete the folder keychain using diskaid which i did and now my phone remains in ''iPhone disabbled'' connet to itunes.
Please someone should help me.

Proof of purchase and bring into a store so they can get you into phone, if after you download iTunes go to the itunes store and find my device and click on your email. How you set it up. Good luck!