The New York Times advertisement for Firefox 1.0 runs today. The initial goal was to pay for it by raising 2,500 contributions in 10 days. They ended up with $250,000 raised by 10,000 contributors.
Asa Doltzer has a PNG version. It’s a well-designed ad. Two full pages.
Your intrepid reporter was there, by the way:

Ben Goodger, lead engineer:
Netscape had it by being first.
Microsoft has it by being everywhere.
Firefox will have it by being best.We’re coming.
