Martin Varsavsky, the founder of FON, has announced that there are now Mac and Linux beta versions of the company's proprietary software. The Mac version requires an Intel processor; the Linux version requires runtime Tcl/tk and the Universal TUN/TAP driver (tun.o), both of which are said to be included in Ubuntu. FON offers a unique business model: as long as subscribers agree to sell their home WiFi access, which is marked on a public map, they are similarly entitled to use hotspots around the world for free. Besides computers, the hotspots can also be connected to with Skype-FON VoIP phones, and any Symbian S60 v3 phone, such as those in the Nokia E-series.