It was even more simplier; just activate the wifi on elementary os, and then the router option on your smartphone, and follow the isctruction on its screen, pick the SSID that you cell tells you and the relative password and then click on the SSID showd by elementary os, supply the password and you're done.
I guess it maight be a little different becaus of ...
Actually, there is an article on fosslinux.com about it but it needs a manual adjustment on the connection profile file, located in:
replacing mode=infrastructure and change it to mode=ap
Anyone has tryed and works?