So you want to write software for the PSP? You have a number of development choices, from C/C++ to easier scripting languages like Lua. The links below will help you get started. If you have any questions, please feel free to post in the forums or just send me a message and I'll do the best I can to help you or point you in the right direction.

Note: I go over how to install the PSP SDK and toolchain in my book, Hacking the PSP, which you can purchase on Amazon, or at most local book resellers like Barnes & Noble and Borders.

Development Environment/Resource	Recommended For	Links
C/C++ via the PSP SDK	Intermediate+	go
Lua Scripting Language	Beginners+	go
Open GL for PSP	Intermediate+	go
PSP API Documentation Project	Beginners+	go

C/C++ via the PSP SDK

To get the most out of the PSP, including getting as close to writing to the bare metal as you can with publically available tools, C/C++ is the way to go. You can do almost anything with your PSP with these tools. You'll need both the PSP SDK, which contains the software development kit, and the PSP Toolchain, which sets up the development environment for you. On Linux you don need anything else. On Windows you will need Cygwin, a Linux shell that runs inside Windows, to do your compiling, although you can use any code editor you desire, even Microsoft's .NET Express editions, which are great tools.

Download links:

Instructions for installing Cygwin and running the PSP Toolchain (download this first and read it through once)
Cygwin (download this second)
PSP Toolchain (downloads and installs everything you need, including the SDK, get this last)

Lua Scripting Language

For those of you new to software development or just wanting to write a quick application, C/C++ is likely the hardest route to take. Thankfully, a much easier development language has been created - Lua. Lua uses simple scripting syntax and easy to understand language structures to make writing games and applications easy on the PSP. Lua doesn't make "EBOOT" files, which are PSP applications. Instead, you build your Lua application, which runs through the Lua Player, similar to how Java applications run using the Java virtual machine.

Open GL for PSP

Open GL is a powerful graphics description language for many computer platforms. It has also been ported to the PSP. If you're familiar with OpenGL, then PSPGL may be a better fit for your game development needs.

PSP API Documentation Project

Many talented developers have dedicated their time to creating APIs (Application Programming Interfaces) for the PSP. Unfortunately, with so many individual developers it has been difficult to find all the developer APIs in one place. The PSP API Documentation Project (also called the "PSP API Documentation Proyect") aims to solve this by offering a central location to find all the APIs. Click the link below to check out the site.