Dear All,
i had bought an iphone 3GS , firmware 5.1.1 to send to Nepal through ebay. It was not an unlocked phone so i wanted to unlock myself and was playing with it when somehow the software 5.1.1 got deleted. Do you guys know how to restore the software? Help much appreciated.
Thank you.

 5.1.1 is the latest version of IOS, so connect it to itunes and click on restore. If for some reason you cannot restore using itunes, download the firmware 5.1.1 ( Link here:iPhone 3GS ) 
put the phone on DFU mode by pressing and holding power and home button until the apple logo appears, then release the power button. (http://www.idownloadblog.com/2010/12/01/how-to-put-iphone-in-dfu-mode/ )

there are tons of video on youtube about it.  

HI if you want to unlock your iphone 3gs from network lock to freely use it in Nepal .Then have a look at sites like WickedUnlock.com here they are rendering remote unlocking service to unlock all model iphone from network lock .....You first verify that whether they are rendering service for your country and network provider .If yes then pay for it and unlock your iphone.You can easily restore your iphone using itunes ....