Jailbreak and unlock are two different things.
Jailbreak just allows you to run uncertified applications - once jailbroken you can run one such application (ultrasn0w) to unlock.
However, 3.1 cannot be unlocked - by anyone.
When it can you will see it on the dev team blog.
Dev-Team Blog
Like it says right at the top before doing anything with 3.1 read it carefully as you can jailbreak, but it's not straightforward like it was for 3.0. If your 3.1 has had it's baseband upgraded (likely as it will have been updated in iTunes) then it's not certain that there will ever be an unlock at this time - although I'm sure they are working as hard as they can.
If you connect it to iTunes will it tell you the firmware version ?