I've collected links to the sites, where you can pre-order Madonna's official 2008 calendar. Most of these shops ship worldwide.
Link to the two pictures from the calendar (front and back side).

USA
http://www.amazon.com/Madonna-2008-Calendar-Signatures-Network/dp/0740770888/ref=pd_bbs_sr_1/102-1595326-9371337?ie=UTF8&s=books&qid=1190110767&sr=8-1

Japan
http://www.amazon.co.jp/dp/0740770888/ref=s9_asin_title_2/249-3304961-0033148?pf_rd_m=AN1VRQENFRJN5&pf_rd_s=center-4&pf_rd_r=1X24MR3N3EVNHY46JAT8&pf_rd_t=101&pf_rd_p=75778106&pf_rd_i=489986

UK
http://www.amazon.co.uk/Official-Madonna-A3-Calendar-2008/dp/1847700357
http://www.danilo.com/Music/Products/Madonna
http://www.play.com/Books/Calendars/4-/3472078/-/Product.html?searchstring=madonna&searchsource=0

Germany
http://www.libri.de/shop/action/productDetails/6431170/madonna_2008_the_official_calendar_3831839395.html
http://www.amazon.de/Madonna-2008-Calendar-Signatures-Network/dp/0740770888/ref=pd_bbs_sr_1/302-3492400-4982468?ie=UTF8&s=books-intl-de&qid=1190295285&sr=8-1

Canada
http://www.amazon.ca/Madonna-2008-Calendar-Signatures-Network/dp/0740770888/ref=sr_1_1/701-0693056-4395550?ie=UTF8&s=books&qid=1190295453&sr=8-1

France
http://www.amazon.fr/Official-Madonna-A3-Calendar-2008/dp/1847700357