There's an excellent entry from January on Brainstorms & Raves blog about standards for Web site organization and ways to create user-friendly URLs.
Excerpts:
This article is just as timely today as it was when it was written in 1998: A Standard for Site Organization, by Greg Knauss (with several brains and contributors) at Stating the Obvious. The example root level site structure makes a lot of sense for visitors and for developing and maintaining a website.
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For more on friendly URLs, these posts also include links to helpful information and resources: