Thanks. Found some code relating to that.

Code:
DEFINE OSC 48
    @ __CONFIG   _CONFIG1L, _PLLDIV_1_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
    @ __CONFIG   _CONFIG1H, _FOSC_HSPLL_HS_1H
    @ __CONFIG    _CONFIG2H, _WDT_OFF_2H & _WDTPS_512_2H
    @ __CONFIG    _CONFIG3H, _PBADEN_OFF_3H & _MCLRE_OFF_3H 
    @ __CONFIG    _CONFIG4L, _LVP_OFF_4L & _ICPRT_OFF_4L &_XINST_OFF_4L
Opened the datasheet and tried hard so something enters my thick brain but
I want to ask:
What does _PLLDIV_1_1L mean? There are 3 fields PLLDIV0, PLLDIV1, PLLDIV2. If a 4MHz OSC is used, I guess these fields should be 000. What is PLL anyways? What is the difference between XT and XTPLL? If I am using XT OSC and a 4MHz crystal/resonator, and choose CPUDIV0/1 to be 00, does that mean the PIC will work at 4MHZ & NOT 4/4=1MHZ? If I do not want to use USB then what should be the setting? If I want to have an 8MHz oscillator which field should I change? Why on top it says DEFINE OSC 48 when the author used a 4MHz oscillator with the above settings?

I have many questions like this popping in my mind at this time, all I found is code but no explanation attached and even with datasheet, nothing is making perfect sense.