Use this link for the datasheet.
**broken link removed**
The output of the sensor (Page 5 of the above datasheet, "Basic temperature sensor") is 10 mV/C. You can put an OpAmp to buffer that signal, but don't have to. Connect its output to the ADC's input and the ADC will give you the digital reading.
In your PIC, you should first calibrate the reading.You should put the sensor in 0 degrees Centigrade and measure the corresponding digital output value. Make it your 0 (or better, make it 1000 000 in PIC, so that values from 0000 0000 to 0000 1111 are negative and from 1000 0000 to 1111 1111 are positive).
Good Luck,
TI|CP