PHPLinq is a class library for PHP, based on the idea of Microsoft's LINQ technology. LINQ is short for language integrated query, a component in the .NET framework which enables you to perform queries on a variety of data sources like arrays, XML, SQL server, ... These queries are defined using a syntax which is very similar to SQL.
Some illustrations are included - querying an array, performing a database query and finding data in an XML file. You can find out more about the tool and download this latest version from the project homepage.