DIY A/B/Y pedal schematics?

I'm sort of looking into getting an A/B/Y pedal but then it occurred to me that perhaps I could save a little bit of $ and also practice some soldering at the same time by building my own. Does anyone have schematics (or better yet, build instructions) for a simple A/B/Y pedal?

Hi! Here are two simple A/B/Y/ boxes.
http://singlecoil.com/docs/aby.pdf
And here is an active one.
http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=16&Itemid=26