As of today Prague has four new metro stations. The Green A line has been extended to Nemocnice Motel in the east of the city. As the Green line is the main line taken by travellers going to and from the airport, it is likely initially to cause confusion. For starters all those tourist books about Prague are suddenly out-of-date.You can download a map of the Metro and Bus stops at http://www.dpp.cz/en/transport-around-prague/transit-schematics/, however the changes are shown in the picture above (click to see a larger version).
Travellers coming from the airport will still catch the 119 bus, but it now terminates at the Nadrazi Veleslavin Metro Station and not Dejvicka. There are a number of changes to the bus services in that area and the number 2 tram has been cancelled, but these are hardly likely to impact on visitors or indeed many Prague residents.