pic 18:4550 is the internal osc accurate enough for USB?

I know the 1% internal osc is fine for serial, but is it good enough for USB? On pics with usb harware built in?

No, The internal oscillator can't be used for usb on chips such as the 18f4550.

There is a section (2.3) in the manual which shows the choice of crystal oscillator frequencies and configuration settings to achieve low or full speed usb clock and the instruction clock frequency.

+/- 0.25% accuracy is required per full-speed USB specifications. There is very few PIC meet this standard.

The New PIC18F46J50 can only be used for low-speed USB with internal oscillator. It is better than nothing.