Rail

International trains arrive to the Main station, which is a beautiful art nouveau building with communist period lower halls. This station is sometimes called Wilson station and is centrally located on the red tubeline C. Your train may stop at Holesovice station, which is on red tubeline as well, but it is better to wait for the last stop.

Road

Obviously being a land locked country travelling by road is very easy in fact you can drive or be driven across the border from Germany, Poland, Slavakia or Austria and if your really clever perhaps all 4 at once :-)

There are a number of international coach opperators that either operate out of or into Prague. From the UK there are two main companies Capital Express and Kingscourt Express both run from Victoria coach stationin London to Florenc coach terminal (or near enough) which is the main coach station in Prague.
The Florenc terminal is situated next to the Florenc tube station which servers both the red C line and the yellow B line, and is also a main station for numerous trams and city busses so don't be worried about getting stranded.
which is situated and is near tube station red tubeline C or yellow tubeline B. Late night arrivals can take a night trams or a taxi. The easiest way where to buy coch ticket is Cedok travel agency.

Of your planning to drive why not Czech out shells routeplanner to help you stay on the right track opps I mean road (Warning: driving on train tracks can seriously damage your health.)