Wired today has an article on the preliminary Google logo designs  – something that aspiring internet commercial artists should check out.
One of the designs is obviously referencing Op Art to give a modernistic feel. Another treats the second “O” as a sort of loose metaphor for the web or to symbolize multidimensionality. Yet another uses a magnifying glass for the second “O” — a much more literal representation for a search engine which we used to see really frequently in the earlier years of the internet (remember stuff like the old WebCrawler logo?).
I think the version they ultimately used is the best/strongest one, even though I think it likely owes something to eBay’s playful/colorful logo.
The original designer of the Google logo was Ruth Kedar, an assistant professor at Stanford at the time. She noted, “I had no idea at the time that Google would become as ubiquitous as it is today, or that their success would be of such magnitude”.
Ubiquitous it is indeed. As I noted  two months ago, the frequency of use of the Google logo and its familiarity within the popular culture have been growing to the point of actually being a little bit of a danger from the viewpoint of being able to protect the marks as intellectual property.