Lost with 3G -> Unlock

[cenobyte]

Please forgive my total n00bishness.

I have recently purchased a used iPhone 3G (stats below) and cannot figure out how to unlock it from the previous owner's carrier. I've been told alternately that it cannot be done and that it can be done but that there's a danger I will ruin the phone forever (boo). I'm not averse to farting around with it, but I've received so many differing instructions and have tried to wade my way through everything here, but am just completely lost. So any definitive-ish solution suggestions are really welcome.

The poop:
iPhone 3G 8GB
Carrier (current): Rogers (I want to use a different carrier)
Firmware version: 4.1 (8B117)
Baseband: 05.14.02

I was able to activate the phone by purchasing a $10 SIM from Rogers, and so I can use it as a glorified iPod Touch, but would really like to actually be able to use it as a phone. I have a SIM from my preferred carrier, which has been activated, but the iPhone won't recognise it.

I have tried to jailbreak and downgrade the firmware to 3.1.3, and that seemed to go well, but I was told I couldn't downgrade the baseband, and that that was required to get past the carrier lock.

Help?

[Poseidon79]

There is no unlock for the 5.14 baseband currently. Firmware 4.2 is scheduled to come out this week so do not upgrade your phone again. You'll just have to wait for the next unlock to be released.

[cenobyte]

That's about as pat an answer as anyone could ask for.

Thanks! I shall commence waiting.

[eyeRobot]

Worth trying fuzzyband in Cydia while you are waiting, a few 3G phones are able to downgrade their baseband. Fuzzyband will soon tell you if yours is not one of those....