1) contributing forum members & Elite Team donators... Request a free unlock with your IMEI & email. - if you have an account that has a) existed for a good few months and b) you actually contribute to the site (technical wizardy, or general helpfulness - CONSISTENT AND REGULAR POSTING), then just drop me a message and it's yours, if you don't meet both a) and b) then don't bother - having an account that you rarely posted from is NOT in the least bit interesting.
2) everyone else (new accounts/unregistered/sod all posts, this means you): Get Sec / CID / SIM Unlocked Here
for those who don't know:
Security Unlock lets you flash radios from other devices... technically speaking you can flash any radio, but some will brick it (such as Topaz) - however, Diamond, Raphael and Kovsky should all be fine. It can also be an insurance policy against evil radios - people who had the Kaiser radio from hell will know what I mean.
CID unlock is largely redundant, however, it's quite useful if you like to keep your device on a stock SPL as it means you can flash any official ROM regardless of which brand it's intended for without changing SPL.