Carphone Warehouse offers 'free broadband' (fixed voice + 8 Mbps ADSL for 21 GBP/mo). Orange UK the same (mobile + 8 Mbps ADSL for 30 or more GBP/mo). And now Tele2 Spain offers 50% off your line rental charge.
Basically, all it is, is cross-subsidising and continuously falling prices (equipment, wholesale, retail). Also, establishing a market position by sacrificing margins and aiming for large volumes. Finally, it will force the weak-of-cash out of the market.