The LG Viewty is a complete pain to unlock. I paid for a unlock code from one of the internet unlock sites but they were unable to calculate what the code should be. Got my money back no problem though.
I then managed to download unlocking software for free and it kind of half worked. The viewty was on three and now works with vodafone as well but not o2. The software also reset the IEME number of the handset.
Best advice is to take to a shop and stump up the cash for them to do it.
Keith.