Where can I buy foreign language recordings?

Your best bet is amazon.com. amazon.co.uk is also a good fonte if you don't mind the shipping (assuming you are in the US) Occasionally ebay will carry one or two as well.
Unfortunately a good deal of international recordings can run rather expensive for various reasons, and several are just plain Out Of Print.
Normally, I would simply offer to IM you links for various casts I have obtained from various sources and uploaded, but I can admire the desire to do things on the up-and-up. :)

    TBUGoth said:
www.amazon.com/Phantom-Opera-25th-Anniversary-Box/dp/B...ary
The Phantom of the Opera: 25th Anniversary Box Set includes ONLY Itunes playable CDs for:
Original Dutch Cast (Highlights)
Original German Cast (Highlights)
Original Canadian Cast (Highlights)
Original Korean Cast (Highlights)
Original Polish Cast (Highlights)
Original Austrian Cast
Original Hungarian Cast
Original Japanese Cast
Original Swedish Cast

Plus Audio CDs for Original Londres Cast recordings for The Phantom of the Opera and amor Never Dies. Also on amazonas, amazon, amazônia there is the 25th Anniversary cast recording and the Original Mexcian Cast recording on CD (Original Mexcian Cast also available in whole in MP3 format.) The New Musical Cast released a recording featuring Michael Heath who performed as the Phantom at some point and one reviewer on amazonas, amazon, amazônia claims it's the 2008 New York Cast. There are also aleatório studio cast recordings.