I am working on my first PIC project; a device to keep time and
automatically water some plants.  My question centers around the
steps nescessary to set up the '61 (or '84) to use interrupts.

Using MPSIM on the following code, the ISR is never reached.

; variable declarations
tempW           EQU     0x20
tempStatus      EQU     0x21

; program space
org 0x0000
RESET_V         goto    START
                nop
                nop
                nop
INT_V           movwf   tempW
                swapf   STATUS,W
                bcf     STATUS,RP0
                movwf   tempStatus
                ;               ; interrupt service routine
                bcf     STATUS,RP0
                swapf   tempStatus,W
                movwf   STATUS
                swapf   tempW
                swapf   tempW, W
                retfie

START           bsf     STATUS, RP0
                clrwdt
                movlw   B'10100000'             ; enable timer 0 interrupt &
                movwf   INTCON                  ; enable interrupts
loop            goto    loop