Visas are not required for anyone from the United Kingdom, European Union or United States if the visitor is staying in Prague for less than 180 days.
If a visa is required for an extended stay in Prague, the visitor's passport must be valid for the entire duration.
If a visa is required for a stay longer than 180 days, the passport must also be valid for three months following the end of the visa. If your passport is about to expire and you need to stay more than 180 days, renew it before departure or visit the American Embassy in Prague.
For people from countries other than the United States, staying in Prague on a visa, be sure your passport is valid for one month after your visa ends.
To apply for a passport visit this website: http://travel.state.gov/passport/passport_1738_2.html, or visit your local post office.
