Tools used, in no particular order

Ant - Made the development process a million times easier.

Java - The language used, couldn't do much without it.

Stylus Studio - The best XML editor out there. Used to preview XSL transformations and anything XML-like.

JUnit - Used to unit test parts of the code. Essential to ensure the code's behaving right.

The GIMP - Probably the best free graphics program out there. Highly recommended!

SSH Secure Shell - A stable, reliable SSH client.

Microsoft Visio - Used to produce the UML. Flows better than its stuttery Java equivalants.

Tortoise CVS - A great CVS client that makes Windows Explorer an easy to use CVS environment.

Eclipse - The King of the IDE's where all the code was produced.