I'm not sure if this has been posted before, but I've stumbled upon something nifty. It's a flash program that lets you drag and drop different pick ups/hardware/design elements onto an image of a guitar. You can change the wood type, style of burst etc. Good to help you visualise a project and lay everything out before you commit and start buying parts and paint.

Could also be a useful means of explaining customisations in a way that might transcend the language barrier when placing a custom order

http://www.usacustomguitars.com/virtual-guitars/