From what I've read about Ginger Beer Plants it's just regular ginger and sugar and yeast, there's nothing special about them and they require no specialised kit to start.
The plant of the above statement refers to the 'industrial' kind of plant and not the 'growing' type, I can see where it would become confusing if you didn't already know. It's like they do with vinegar where the stuff is brewed into what is called a mother and you use this to kick start your fermentation of ginger beer, I've read a few posts over at Jims Beer Kit Forum about making ginger beer and it's just a matter of adding ginger and sugar to a one gallon demijohn over a period of time until the yeast can't take any more and then you use that as the beginnings of your 40 pint beer.
As for growing Ginger I believe it's just a matter of putting a stalk of root on top of the soil and letting it make it's own way in.
Have a look at this...
http://www.cookingforengineers.com/foru ... highlight=
