Allright... this is just from the top of my head, so don't hold me to it if it's not perfect.
What I suggest is perhaps an array of levels, which contain a boolean for the lock/unlock of that level.
if you want to use simple level indications (like 0, 1, etc) this could be an idea:
var levelArray:Array = new Array(true, false, true);
This would make level 0 unlocked, 1 locked, and 2 unlocked. Locking/unlocking is pretty easy, if you want to lock level 2, simply say "levelArray[2]=false;"
If you want to use specific names for the levels (could be useful if you have a non-linear level structure) you could use most of the code above.
var levelArray:Array = new Array(); levelArray["home"] = true; levelArray["outskirts"] = false; levelArray["city"] = true;
...making 'home' and 'city' unlocked, and 'outskirts' locked. Locking/unlocking is the same as before... levelArray["outskirts"] = true;
Now that you've got the level array, you could make buttons for each level... I don't know the AS for it, but it could be something like this...
if(levelArray[1]){ create button at the desired location. }
I hope this helps to get you on the right track! Good luck!
