Thanks for the comments:

I've tried using the LDR in series with a 10K pot between 5v and GND, connecting GPOI.0 to the junction between them and still can't get anything meaningful for the value of the variable that stores the ADC readings.

I've corrected the code thus:

Code:
ASM
 __CONFIG _INTRC_OSC_NOCLKOUT & _WDT_ON & _PWRTE_ON & _MCLRE_OFF 
endasm

' Hardware configuration
' ======================



TRISIO = %001111 
ADCON0 = %10000001 
ANSEL = %00110011 
DEFINE ADC_BITS 8
DEFINE ADC_SAMPLEUS 50 
CMCON0=7

Motor1 var GPIO.4
Motor2 var GPIO.5

ADChannel0 var byte

GPIO = 0 ' clear all output
Pause 50 ' internal oscillator settle time

main:
low Motor1
low Motor2
adcin 0,adchannel0 ' Read AN0

If adchannel0 >10 then
  high Motor1
  Low Motor2
pause 5000
low Motor1
low Motor2

endif


goto main