You may eventually decide that you want to write firmware modifications for the x0xb0x. Since x0xb0x is an open source platform and the code is written using free tools in a well known language, its pretty easy to get started with writing new code.

The AVR microcontroller has a wide variety of development tools available. Almost all are discuss/reviewed/available from AVRfreaks, the de facto website for AVR information. This is how I set up development for AVR.

Windows:

1. Download the latest distribution of WinAVR from sourceforge & install it! (The install document available is pretty good, I suggest you read it)
2. Download the latest x0xb0x firmware source code distribution & unzip the archive into wherever you intend to write code.
3. Open up a command window, and go to the development directory and run make
4. If the computer cant find "make," check if the environment variable PATH contains the correct directories (read C:/WinAVR/WinAVR-user-manual.html or wherever you installed WinAVR)
5. There should be a lot of stuff happening now. Eventually it will stop and there will be a file created called 'x0xb0x.hex' which you can then upload into your synth via the bootloading mechanism.
6. Now write some code! If you add new files, be sure to change the Makefile to include them in the build.