>  So are you saying that if someone was to use a pin on port B with
> the interrupt on change, that the rest of the ports pins shouldnt be
> used for any other application?
> I don't quite understadn what you meant.

That's pretty much what it means, I'm afraid.  Basically there is one real
use for the interrupt-on-change feature that actually works fairly well:
using a PORTB trigger to wake from sleep.  While this will not be 100%
reliable in cases where the trigger condition may be "pre-existing", it is
good enough to be used for things like remote controls and items like that.

Further, even in a remote-control context it may be possible to make the
port B trigger reliable: if one can ensure that all the inputs WILL be in
an inactive state before the last time portB is read before sleep, then
any time they become active will cause an interrupt.  For example, assume
a keyboard is wired 4x4 using PB0-PB3 as output and PB4-PB7 as input.  The
following will cause the CPU to go to sleep but re-awaken if and when any
button is pushed [assuming pullups on PB0-PB3]:

        bsf     RP0     ; Bank 1
        movlw   $FF
        movwf   PORTB   ; Set TRISB to all inputs
        bcf     RP0     ; Bank 0
        clrf    PORTB   ; Prepares PORTB to ground outputs 0-3, but doesn't
                        ; do it YET [because of TRIS].
        bsf     RP0
        movlw   $F0
        movwf   PORTB   ; Set 4 LSB's to low outputs.  NOTE: This instruction
                        ; does NOT access PORTB and so cannot clear the PORTB
                        ; latches!
        bcf     RP0     ; Back to bank 0
        ...
        sleep           ; Frere Jacques... dormez-vous?