112 - Emergency Central

112 is the general emergency line throughout the European Union (similar to 911 in the U.S.) It should be used for large-scale emergencies, especially for those who don't speak Czech - operators will speak English and German as well as Czech.

158 - Police
156 - City Police
150 - Fire Department
155 - Ambulance
1180 - Information about telephone numbers

Also, important numbers for car trouble or road services:

154 - Towing Service
1230 - Emergency Road Service (ABA)
1240 - Emergency Road Service (UAMK)

257 271 111 - Nemocnice Na Holmolce (Prague 5)
222 801 111 - Nemocnice na Františku (Prague 1)
261 081 111 - Fakutní Thomayerova nemocnice s poliklinikou (Prague 4)
224 431 111 - Fakultní nemocnice v Motole s poliklinikou (Prague 5)
267 161 111 - Fakultní nemocnice Královské Vinohrady (Prague 10)

+420 224 125 353 - Visa
+420 222 800 111 - American Express
+420 261 354 650 - MasterCard/Eurocard
+420 267 314 285 - Diners Club

There are a few over-the-phone information services that are offered by Cesky Telecom, usually for a steep price. Note that many of the services are offered only in Czech.

187 - General Information
1180 - Info Line: Czech Number Directory
1181 - Info Line: Foreign Number Directory
141 11 - Operator for changed numbers (information about renumbering)
141 16 - Weather
141 20 - Medical Information

Calling from abroad to the Czech Republic

dial 00 420 + local number (9-digit number)

Example: If you would like to hire a guide (Prague Information Service)
dial 00 420 + 236 002 562

There are some exceptions.

Example: If you would like to ask for information by phone (Prague Information Service)
dial 00 420 + 12 444

Calling abroad from the Czech Republic

dial 00 country code + local number