My background is mainly .NET, including the ASP and VB components. I've also worked a good bit with MSSQL. However, I'm looking at building a new application and wondering if I should create it in PHP / MySQL. If so, I'm wondering what tools might be available to assist in rad development via this platform? It is essentially a niche CRM I'd be building, so any suggestions along that venue would be appreciated. I expect it to perform basic CRUD operations.
The most popular IDEs are based on Eclipse - either Zend Studio, itself based on the PDT plugin, or Aptana. For MySQL work, the MySQL Workbench is a must. They all come with many tools. There is also NetBeans, widely used but I can't judge it as neither I, nor anyone I worked with, used it.
There are lots of tools to be used for PHP development - from Ant / Phing for build jobs, XDebug, PhpUnit for testing... if you are a newbie, the Zend framework is a good starting point, it covers absolutely everything and it's PHP's closest equivalent to .NET development. Some people find it a bit bloated and prefer doing everything with smaller, hand picked tools.