If he has the PIC connected to a max232 hooked to a PC serial port the RX pin should already be held at logic 1 through the max232.

http://www.rentron.com/Files/bMAX232.gif

PIC to PIC using the hardware UART the tx pin on both will idle high so that works also without a pull-up. Even bit-banged serial should hold the tx pin at the idle logic state during idle periods.

But;
Device = 18F4550
Xtal 20

Indicates he's probably using the Proton compiler, so I would post the question there. It's most likely a configuration problem. Without config options in your code you're using whatever defaults they have in the include file, so it's probably not running at 20MHz.