Share Web through another port I have a webserver running on a MBA at port 4431 and I want to access through my local network.

But web sharing uses port 80 by default and I can't access to my_mba_ip:4431

Can I add ports to web sharing? I found this old, old post (Changing the OS X Web Server Port) where seems the solution to my problem, but I don't know how to do that in Lion :(
The location of the httpd.conf in lion is the following: 

/private/etc/apache2/httpd.conf


And you will search for the line to change that has the following: 

Listen 80


The rest of that document you linked should work.

I would however recommend using MAMP for much better control of apache and mysql. 

MAMP