Create a WPA hotspot I would like to share my wired connexion by Wifi. 

As you may know, Mac OS Internet Sharing option doesn't support more than WEP security protocol. In other words, it's creating a nearly opened network.

Is there any software able to create a more secured Wifi hotspot (at least WPA) compatible with Mac OS ? Something like Connectify or Virtual Router under Windows 7.

I have a MacBook Pro (15-inch, Early 2011).
AFAIK it's not possible in Mac OS X as it is now.

Windows tools you've mentioned are probably relying on Windows 7 native ability to create ad-hoc WPA-protected networks. There is no support for that in Mac OS X and since WPA encryption on ad-hoc network is not defined by the WPA standard it will probably never be.