If I'm for example using a PIC16F628a I do the following to figure them all out (probably the wrong method, but it's the way I do it)
I open the file:
C:\Program Files (x86)\HI-TECH Software\PICC\std\9.60\include\pic.h
(may be a slightly different path on your system, eg. if you use a 32-bit system you wouldn't have the (x86) in the path, or maybe PICC18 if programming with a PIC18 device)
In this file I see that the pic16f628a uses the file pic16f62xa.h (searched for 16F628A), so I open the file:
C:\Program Files (x86)\HI-TECH Software\PICC\std\9.60\include\pic16f62xa.h
At the bottom of this file, I see all the Configuration Mask Definitions:
// Configuration Mask Definitions
#define CONFIG_ADDR 0x2007
// Protection of flash memory
#define PROTECT 0x1FFF
#define UNPROTECT 0x3FFF
// Protection of EEPROM data memory
#define CPD 0x3EFF
#define UNPROTECT 0x3FFF
// Low voltage programming enable
#define LVPEN 0x3FFF
#define LVPDIS 0x3F7F
// Brown out detection enable
#define BOREN 0x3FFF
#define BORDIS 0x3FBF
// Master clear reset pin function
#define MCLREN 0x3FFF
#define MCLRDIS 0x3FDF
// Power up timer enable
#define PWRTEN 0x3FF7
#define PWRTDIS 0x3FFF
// Watchdog timer enable
#define WDTEN 0x3FFF
#define WDTDIS 0x3FFB
// Oscillator configurations
#define RCCLK 0x3FFF
#define RCIO 0x3FFE
#define INTCLK 0x3FFD
#define INTIO 0x3FFC
#define EC 0x3FEF
#define HS 0x3FEE
#define XT 0x3FED
#define LP 0x3FEC
Each selection is basically separated by a commend line, so I would make my config word as follows (just an example, select what you'd use for your particular application):
__CONFIG(HS & WDTDIS & MCLREN & PWRTDIS & BORDIS & LVPDIS & UNPROTECT & UNPROTECT);
Now whether putting UNPROTECT in there twice actually does anything, I don't know, but it shows up twice in the include file, so I put it in there for "completeness". Here I've configure it to have an external high-speed oscillator, disabled the watchdog timer, enabled the Master clear reset pin function, disabled the power up timer, disabled the brown out detection, disabled low voltage programming, unprotected EEPROM data memory and unprotected the flash memory.
Hope this helps!