In his most recent blog post Michael Nitschinger introduces you to Couchbase, a document-oriented database, and how to use it with PHP.
As there were a lot of merges, renamings and releases, it was pretty hard to follow up with the current/best database version and SDK to use for your project. Now as the dust has settled a bit, here's what I've come up with: Couchbase 2.0 will be the next major version and is already pretty stable, so I'll jump straight onto it and skip 1.8.
He recommends using the php-couchbase libraries or the php-ext-couchbase extension. He walks you through the whole process of getting Couchbase installed and running and the PHP support installed via the aptitude package manager. A sample script and some basic usage information is also included.