Large ziploc-type bags highly recommended for this. You can get them from a supply place like
www.uline.com.
Ziploc used to sell huge zip bags with handles (called "ziploc big bags"). I think they are discontinued, but you can find them on ebay for a few dollars. They are about 2 x 3 feet. Very useful for all kinds of purposes.
Also look at suppliers such as:
http://www.spiritedshipper.com for the immediate padding. I used these to bring 35 bottles of beer back from Belgium last month in my regular luggage and they worked great; they can be adjusted to different sizes of bottles:
http://www.spiritedshipper.com/inserts.html