Gustav Eklundh has posted a whole series of search type implementations to his blog - here's the list so far:

• Quicksort
• Gnome sort
• Strand sort
• Merge sort

He briefly explains each of the sort methods in each of the posts, sometimes with links to external sources (like Wikipedia) for more information on the method.

On the PHP-Coding-Practices site, there's a sort of case study posted showing how the author (Tim Koschuetzki) took a chunk of code that was slow at sorting an array and sped it up dramatically using the Quicksort Algorithm.

Today in the morning I had a very unusual programming job to do - or at least what is for me rather unusual. I was confronted with the question whether it is easy to implement the quicksort algorithmn to sort an array of arrays based on a key in the second-dimension of the array. Join me to find out.

The key to the transformation is an application of the Quicksort method that applies a filter to the elements in the array and places items to the right and left of the pivot point. To illustrate the point, he includes both the pre-quicksort code and post-quicksort.