not strictly an iphone, but ive used these anonymous unlocking services multiple times and theyve all worked. pay with paypal, while sending in my IMEI.... in 5 minutes or so receive the unlock code and bam.
very little monetary risk (20 bucks or fewer)... no security or other risks.
dont know if its chinese or russian farms with cracked algorithm or rogue employees with IMEI hash or what, but its worked.