In this brief article I go through how to create master page(s) on the web server that appear in the Master Page settings for a site collection for the Collaboration Portal or Publishing Portal site templates. This will be useful if your requirements entail using one or a few master pages for several site collections and you need to not create multiple versions of the master page in various content databases. This allows you to create a single master page, use as many times as you like, and update it in one single location on the web server.
» How to Create and Store Master Pages on the Server for Use with Site Collections
UPDATE 10/19: I posted a better way to do this here: Create a Feature: Master Pages for Site Collections