AIDS (AJAX Image Dump System) is a simple, yet powerful AJAX-based image host system. It's geared toward forum usage, and it generates bb-code for cutting and pasting into forums that support bb-code. It lets people create user accounts to keep track of their pictures, reaccess them later to view stats, delete them, or simply copy the bb-code again.
AShopV provides a shopping cart with digital goods delivery, affiliate tracking, Swoopo-style auctions, full PayPal support, support for many other payment gateways, many shipping calculation options, and multiple languages and currencies. The software also includes a CRM Sales Office with order management where you can create quotes and turn them into bills that can be paid online, set up automatic recurring billing, manage purchase orders, handle customer and vendor contact through POP3 or IMAP, and view customer and vendor history. A Shopping Mall integrates with the affiliate tracking to let you set up your own ClickBank clone.
The ATK Framework is a PHP business framework. It is targeted at developers who wish to focus on business logic instead of coding HTML. ATK provides a complete framework that requires only small amounts of code to get usable applications, while maintaining full flexibility. ATK has a model driven approach, but is 100% customizable.
AfterLogic WebMail Lite PHP is a Webmail script with a modern AJAX interface. It supports IMAP accounts, SMTP, and SSL (including Gmail). Users can check and send mail and use an address book. It provides a slick skin, a three-pane view, non-English language support, UTF-8 support, IMAP folders, and viewing and composing HTML mail. A MySQL backend is supported, with Web-based administration and installation and cPanel/Plesk/DirectAdmin integration.