Hi Guys!

This works:

'************************************************* *******************************************
' 16F628A 20Mhz extern canned Oscillator
' damn program should blink an LED
' Yeah Works!
'************************************************* *******************************************

@config_EXTCLK_OSC


DEFINE OSC 20
LED VAR PORTB.7
CMCON = 7 ' RA0-RA3 are digital I/O

TRISB = %01111111 ' RB7 is output, rest are inputs.

main:
led = 1
pause 500
led = 0
pause 500
goto main

END ' End of program

And heres the mistake:
http://hobby_elec.piclist.com/e_pic8_8.htm

Look at the osc wiring diagram: ext osc MUST be connected to RA6! hahahaha!