Thank you all for your response.

mackrackit,

I'm not powering any devices with the USB host 5 volts, but I'm almost 100% sure that the signal comming in and out of D- and D+ on the PIC18F4550 needs to be 5V. That's why a voltage level converter is needed, but I don't know which chip is appropiate.

Aratti,

The GLCD backlight voltage must be around 9.3 Volts. But, the datasheet recomends to use 12V with a current limiting resistor of around 220 Ohms.

Joe S,

The circuit is going to be fed from a rechargeable battery, and a voltage divider will drain a battery very quickly. The battery that I will use is probably a 6.0V lithium battery. I read somewhere that there are some LED driver chips that give you 12V from a 5V or 3V voltage input. But, if this is true I don't what chips these are.

Again, thank you all for your ideas.

Robert