replacing a range outlet
There is a provision in the National Electrical Code that will allow a 3-wire installation, in situations where there is existing wiring (250.140 exception). You should be fine to install a three prong receptacle, and use a three prong range cord. 

There should be special instructions in the manufacturer's installation instructions that are included with the range, that will specify exactly how to attach the 3-wire cord.  

If you're really concerned about it, or want to update to follow modern code. You could install a new 3-wire with ground cable, and use 4-prong receptacle and cord.


  National Electrical Code 2014
  
  Chapter 2 Wiring and Protection
  
  Article 250 Grounding and Bonding
  
  250.140 Frames of Ranges and Clothes Dryers. Frames
  of electric ranges, wall-mounted ovens, counter-mounted
  cooking units, clothes dryers, and outlet or junction boxes
  that are part of the circuit for these appliances shall be
  connected to the equipment grounding conductor in the
  manner specified by 250.134 or 250.138.
  
  Exception: For existing branch-circuit installations only
  where an equipment grounding conductor is not present in
  the outlet or junction box, the frames of electric ranges,
  wall-mounted ovens, counter-mounted cooking units,
  clothes dryers, and outlet or junction boxes that are part of
  the circuit for these appliances shall be permitted to be
  connected to the grounded circuit conductor if all the following
  conditions are met.
  
  (1) The supply circuit is 120/240-volt, single-phase,
  3-wire; or 208Y/120-volt derived from a 3-phase,
  4-wire, wye-connected system.
  
  (2) The grounded conductor is not smaller than 10 AWG
  copper or 8 AWG aluminum.
  
  (3) The grounded conductor is insulated, or the grounded
  conductor is uninsulated and part of a Type SE serviceentrance
  cable and the branch circuit originates at the
  service equipment.
  
  (4) Grounding contacts of receptacles furnished as part of
  the equipment are bonded to the equipment.