The site of Google Custom Search Objective-C library offers a library and a framework to access the JSON APIs. It aims to be flexible to work with Google APIs for iOS and Mac OS X apps. It is compatible with iOS3+ and Mac OS X 10.5+. Available example applications, support, and contributions.
With Twitter reducing its search history to four days, it is a challenge for applications that are dependent on search results, that went not days but even months back. Several applications have taken on the challenge to fill this void and are building search indexes on top of Twitter. Topsy is one of them and it's sharing its results as an API.
Want to launch a site today? There are only two more days to enter the Will Code for Green contest, which will pick five winners of economy- or ecology-themed web applications that consumes Bing search (our Bing API profile).