New to this

Hi everyone. I'm new to the open source development world and am not even sure where to start. I have some background in electronics and design, but it has been many years since I even attempted to do design anything. I actually have something I'd like to design for personal use, and after suggesting it to a few friends, they'd like one as well. So I figured I'd start my research and if things work out well, maybe even bring it to market.

Any suggestions on how to proceed? Good tutorials? My project is a car mp3 player, using a laptop HDD or flash memory with a few more additions if possible.

I'd start by going out on the web and seeing what is already out there, no need (or market) for something someone else is doing already. Then put together a list of what you want it to do and how you want it to do that. Once you have a plan start looking for parts that will do the things on your list. Too many people start with the micro and then ask how do I do this with this part and sometimes the answer is "you don't"