If you're using a mac you're in luck, PHP and the web server are already installed for you, you just need to turn them on an configure a few things and you can run PHP on your computer without an internet connection.
Learning Regular Expressions is key when learning any programming language, this is the book that everyone seems to learn from, it's the only really good one that I know of. Once you understand how they work they can be used for all types of searches, they even come in handy when doing search and replace work on your website.
pommo is an open source newsletter signup system written in PHP. You won't properly appreciate pommo without checking out it's competition. After spending two days installing other PHP mailing lists we are SO HAPPY to have found this one. It's free and it's easy to install and configure.