Amazon's web services have attracted a thriving community, people are making real money building alternate interfaces to Amazon and collecting Associates commissions on the resulting sales, and there are even tool developers who have come up with the creative business model of agreeing with their users to have some percentage of the transactions use the tool developer's Associates id rather than the site owner's. Cool.
Amazon is holding a free all day web services workshop on April 22 at the O'Reilly Emerging Technologies Conference. The event is open to people not registered at the conference (though space is limited to 50 people).
P.S. Slashdot really ought to have web services as a topic area! Despite being over-hyped, this is a really important area, and there's a lot cooking. Amazon's web services"