I have just finished a 2009 calendar featuring opera composers: Puccini, Mozart, Berlioz, Bellini, Mascagni, Rossini, Bizet, Wagner, Handel, Offenbach, Verdi and Leoncavallo. It is at cafepress. I am going to try various POD suppliers to see the differences. I will report here my findings. Cafepress do three formats for their 12 page calendar
Standard Wall Calendar (which I have used) page size 11" x 8.5" (11" x 17" when hung) 100lb cover weight high gloss paper wire-o binding Jan - Dec 2009 US holiday dates only
Oversize Wall Calendar as above except page size 17" x 11" (17" x 22" when hung)
Vertical Wall Calendar page size 11" x 17" (11" x 17" when hung) 10pt heavyweight high gloss paper rest as above.