Also, I thounk you people are confusing marketing with advertising. Advertising is a subset of marketing. Marketing is much broader, and is something PHP has been doing for a long time, via the community. People are pimpin' PHP left and right, and they are not getting paid for it at all. That's most certainly marketing, too!
I also entirely disagree that a product needs any advertising whatsoever to get established. If it's superior to other product on the market, it will more often than not market itself, via word of mouth. I'm thinking about Google and Apache here, for instance.
With that said, PHP could of course do well with some corporate backing. I have not seen any figures, but I bet Linux took a big jump when IBM started pimping it on the B2B market. They did a lot of advertising, too, but the real value was that IBM held Tux under his shoulder and said "It's cool. He's with me." when he walked into the corporate club.
PHP doesn't lack advertising - it lacks trust. I think it will start to gain it when PHP 5 has had a few stable releases.
I also think it needs more standardization in general. A standard class library, a standard way of coding, a standard framework etc. Diversity is good, but in PHP:s case, it's gone way overboard. It needs some "defaults".