Language Integrated Query. Now I know that the acronyms are. I have seen C# examples, but can't really understand them. Can I use them with PHP? Can I use it along with ORM? Has any PHP MVC framework has this?
LINQ is basically a library combined with changes to a number of .Net languages that allows you to write queries against the objects in your program... This is a vast over simplification, but it treats collections of objects in a similar manner to that in which SQL treats tables... The objects within those collections are analogous with a record in a database table, and the properties of these objects are analogous to columns on a table in SQL.
The syntax is a little different to SQL, but it gets easier as you use it.
Can't speak for PHPLinq, but if it's as good as LINQ itself, you're in for a treat...
LINQ is a dotnet technology, so you can't use it outside the domain of Microsoft. LINQ is a way of integrating SQL (and other similar data queries) as syntactic constructs in the language. So it's an extension of the language, not a library.