NS3.3 will run on SOME "bare" P4s, but not all. Generally, Intel chipset mobos are compatible, although you'll probably not get sound, ethernet or high-res video from the on-board components. For those things, you'll need external add-on cards. A combination hardware support list and driver download site is available from
here. (
http://docs.info.apple.com/article.html?artnum=70039)
If you have PCI SB16-compatible card
this (
http://mitglied.lycos.de/Morgon_de/) page is for you. Other PCI soundcard users are out of luck.
Frankly, however, I would use OS4.2 on a P4. The hardware support is somewhat better (as an example, with the Y2K patch installed, you get a video driver that gives you full color on any VESA 2-compliant card) Any part of 3.3 missing from 4.2 can be copied over rather easily.