Need help with hardware and software config on PIC12F675 to light up an LED
If the schematic is correct, then you are setting the wrong pin. You need to set GP0 to 1 (and alter the TRISIO accordingly too)  

EDIT - Okay, see code below. This has been confirmed to work in MPLAB SIM using HI-Tech v9.81.  I tried to comment a bit to give an idea of what is going on. Note I turned MCLR off in the config bits.
The main thing was the Comparator needing to be disabled (CMCON, see comments/datasheet)
I added a (commented) flashing routine in the for loop for interest.
For the GPIO port pins, GPIOx, or GPx  should work fine.

#include &lt;htc.h&gt;

// Define oscillator frequency for delay routines
#define _XTAL_FREQ 4000000 

// Make sure config bits are correct in your version 
//(e.g. v9.61, 9.81, etc) These work in v9.81 but NOT in v9.61 
// Config bits are listed in e.g. Program Files-&gt;Hi-Tech-&gt;PICC-&gt;v9.81-&gt;include  
__CONFIG(FOSC_INTRCIO &amp; WDTE_OFF &amp; CPD_OFF &amp; MCLRE_OFF);

void main()
{
GPIO = 0;               // Initialise GPIO to a known state 
ANSEL = 0x00;   // Analog inputs disabled so we can read state of pin  (e.g. in MPSIM, or needing to read-modify-write)
CMCON = 0x07;           // Comparator peripheral turned off 
TRISIO = 0b11111110;    // Set GPIO0 to output  

GPIO0 = 1;              // Note GPIO0 used, not GP0 (see 12F675 include file in directory mentioned above)

for(;;)
{
    /*
    GPIO0 = 1;              // Uncomment to flash GPIO0
    __delay_ms(100);        // Hi-Tech "built in" delay routine - needs _XTAL_FREQ (oscillator frequency) defining 
    GPIO0 = 0;
    __delay_ms(100);
    */
}


}