The Wolfram Alpha Python Library developed by Derik Pereira allows to access the The Wolfram Alpha webservice API as long as it supports web requests and XML. Due to the use of Python language, developers could work with a simple syntax, deep prototyping, and easy to use data structures. Such operations can facilitate dynamic computations of built-in data, algorithms, and methods, main features of the Wolfram Alpha API.
The Open Library is a project of the non-profit Internet Archive, whose long-term goal is to present "one web page for every book ever published." A recent release of the Open Library brought the total number of book records to over 13.4 million (including over 234,000 records with full-text for the book).
Did you think the search engine wars were over, and Google won? New kid on the block Blekko, currently in closed private beta, urges you to reconsider. Once out, it's bound to become the favorite of search refiners, with the results likely made available as an API.