How do you know your PIC is not working?

Consider the test code below...
Code:
	LED var PortB.0
	TRISB=%00000000
loop:
	Pause 1000
	Toggle LED
	Goto Loop

	End
If your 555 is running at 100kHz it would actually take 40 seconds before the LED lit (with PBP set to a 4MHz default - unless you've told it otherwise). What speed is your 555 running at? Is it running? Have you remembered to tie MCLR to Vdd or otherwise set it to internal?