This is a quick calculator for the most popular PCB manufacturers for prototype PCBs.
Shipping is often approximated, usually UPS ground or whatever is least expensive. This software is also US-centric, costs may be different for Europe, Canada, Australia, etc.
These prices are current as of August, 2007
Since this is a really old project, and I'm not mainaining it anymore, I suggest checking out PCBShopper.com from Bob Alexander - a much slicker and more recent version of the same.
All of these have been either tried by myself or recommended by others but be sure to read up on the manufacturers, and verify things like yield, drill-sizes, and DFM constraints! This calculator is not guaranteed and is offered as-is. Feel free to snag the Javascript code, its public domain.
This is a javascript calculator that will tell you (approximately) your cost for a PCB design. Its only inteded for 'prototype quantities' usually a couple dozen (max) pieces.