I know this is a bit of a longshot, but does anyone one have a copy of the May and June 2008 EPE (Everyday Practical Electronics) magazine and would be willing to send me a copy of the Mini Theremin articles.
A Colleague at work wants me to build him a theremin but doesn’t want to spend too much so I could do with seeing the parts lists to work out the cost before i go ahead and buy the magazines.
E
Basic theremins tend to be all pretty much the same inside… you’ll get a ballpark figure from any theremin schem you can find online
This is the one I built
http://www1.jaycar.com.au/productView.asp?ID=KC5295
Fun toy 
The EPE Mini Theremin looks like it has a bit more to it. IE "3 distinct sound voices.
I’d like to build a very simple one for myself at some point as I reckon it would be a really good addon for one of the spare Ains onthe MB-6582 so will look into the kit you suggested at a later date.
I’ve got one of the kits Stryd mentions. Not too hard to build, good value, though care is needed in tuning, (goes for most Theremins).
I can send you a copy of the Jaycar manual if you like, though the kit is the best deal.
You can buy the EPE editions for download here: EPE back editions