This page could use some help. LinuxMCE is very big; about 12 million lines of code in the daily build process. And that doesn't include all the existing open source projects that come from Ubuntu. We need a good organizational chart to help developers get going, and this is lacking. Sorry... It's high on the todo list.
LinuxMCE is, at least at the outset, largely a fork from Pluto. And Pluto allowed me to import all their existing Wiki pages, including a Programmer's Guide. The information is largely accurate for LinuxMCE too, and there is a lot there that will make a good starting point, but it needs to be better summed up and organized.
Read about the long-term goals and strategy here: History of LinuxMCE, why I started this project, and the goals