Yahoo has one-upped Google with the announcement of their API.
Google has been doing this for a while now (3 years), but you
never hear anything new about it like you do with Amazon's API
where new applications seems to appear on a daily basis.
The SDK
includes BSD-licensed examples in Perl, Python, PHP, Java and
JavaScript (Google's SDK includes Java and .NET examples), and
accesses Image, Web, Video, Local, and News searches (last time I
looked, Google did Web, Cache, and Spelling)! Yahoo's API uses
REST rather than SOAP, which I personally find much easier to
work with.