From fixed phones:

999: Ambulance
998: Fire Brigade
997: Police
981: Road Assistance
986: Municipal Police

Using mobile phones: remember to dial the local code before the number, for example:

22 – 997 to call the police in Warsaw. Emergency calls from phone boxes are free of charge. If you do not know the local code, dial the general emergency number for mobile phones: 112. The operator will request the appropriate emergency unit. We recommend using direct emergency numbers in the case of danger (997, 999, 998) because in some areas the general emergency number (112) still does not work properly.

These numbers may also be useful:

Warsaw public transportation information (22) 94 84
Cracow public transportation information (12) 91 50
International flight departure information (22) 650 39 43
International flight arrival information (22) 650 42 20