A* pathfinding

I'm making a procedural dungeon generating code. The rooms are done, doors are in place and i have an array of the dungeon (actually just unpassable and passable spaces) and an array of the door positions. I wan't to create the passageways now, but I dod not found anything about this. What i actually need is some help. How could I make a algorithm, or can someone link a good article explaining the steps of it, and secondly, how could i weight it?

 

I created my pathfinding-scripts using these tutorials, just watch them all and implement what you need. It's all in there, the procedure, how the pathfinding works at it's core and even weights.

First video of the series:

 

http://www.policyalmanac.org/games/aStarTutorial.htm
This is what I (and others here) read to learn how a simple a* algo works

 

Wow, there's a tutorial I haven't seen in years.

That's the very tut I used way back in 2008, to write my very first A* algorithm as well. In Flash of all things as well... lol.
https://code.google.com/p/lodgamebox/source/browse/trunk/com/lordofduct/engines/ai/AStarMonotonic.as