Hi and welcome.

try the following
Code:
        '
        '       Pic Configuration
        '       =================
        ASM
        IFNDEF PM_USED
            list w=-207
            ;    Program Configuration Register 1
            cfg1 = _INTRC_IO & _WDT_OFF & _PWRTE_ON & _MCLR_OFF & _BODEN_ON & _LVP_OFF & _CCP1_RB0
            cfg2 = _CP_OFF  & _CPD_OFF & _WRT_PROTECT_OFF & _DEBUG_OFF 
            __CONFIG    _CONFIG1, cfg1 & cfg2		    		 
            
            ;    Program Configuration Register 2
            __CONFIG    _CONFIG2, _IESO_OFF & _FCMEN_OFF
            list w=+207
            ELSE
                device  INTRC_OSC_NOCLKOUT, WDT_OFF, PWRT_ON, MCLR_OFF, BOD_ON, LVP_OFF, CCPMX_OFF 
                device  PROTECT_OFF, CPD_OFF, WRT_OFF, DEBUG_OFF    
                device2 FCMEN_OFF, IESO_OFF
            ENDIF
        ENDASM
        OSCCON = %01100000 ' set to 4 MHz clock
        
        '
        '       Hardware configuration
        '       ======================
        TRISB=0     ' Set all PORTB pins to output
        TRISA=255   ' Set all PORTA pins to output
        ANSEL = 0   ' disable adc converters
        CMCON=7     ' disable analog comparator
        
        '
        '       Hardware assignment
        '       ===================
                '       
                '       Push buttons
                '       ------------
                '       Push buttons are connected between PIC i/o and gnd
                '       don't forget to add a pull-up resistor on the i/o too
                '
        ONButton    VAR PORTA.0
        OFFButton   VAR PORTA.1
                '
                '       Light
                '       -----
                '       LED connect between I/O and gnd... with a resistor in serie
                '
        LIGHT       VAR PORTB.0

        '
        '       Hardware initialisation
        '       =======================
        WHILE OSCCON.2=0 : WEND     ' wait 'till internal OSC is stable
        PORTB=0                     ' clear all PORTB i/o 
        
START:
        if ONButton = 0 then
            light = 1   ' turn the LED on
            endif

        if offbutton = 0 then
            light = 0   ' turn the led off
            endif           
            
        GOTO START