The '4550 supports USB, and the oscillator section has a lot of options. Try the following;
asm
__CONFIG _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L

__CONFIG _CONFIG1H, _FOSC_HSPLL_HS_1H & _FCMEN_OFF_1H & _IESO_OFF_1H

__CONFIG _CONFIG2L, _PWRT_ON_2L & _BOR_ON_2L & _BORV_2_2L & _VREGEN_ON_2L
__CONFIG _CONFIG2H, _WDT_OFF_2H
__CONFIG _CONFIG3H, _MCLRE_ON_3H & _LPT1OSC_OFF_3H & _PBADEN_OFF_3H & _CCP2MX_ON_3H
__CONFIG _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _ICPRT_OFF_4L & _XINST_OFF_4L & _DEBUG_OFF_4L
endasm
define OSC 48 'core running at 48Mhz
DEFINE DEBUG_REG PORTA 'pin Porta.5 serial out to debug
DEFINE DEBUG_BIT 5
DEFINE DEBEG_BAUD 2400
DEFINE DEBUG_MODE 0 '0 = TRUE, 1 = INVERTED

This setup works with a 20 Mhz crystal. You will also find more information if you do a search here for 18f4550

Good Luck,
Jerry