The years first ICCF thematic starts 2/15/2007 with entries accepted no later than the 1st of Feb.
http://it.geocities.com/thematic_iccf/webserver/Themes_2007.htm
http://www.iccf.com/
http://www.iccf-webchess.com/
I am thoroughly prepared to get my butt kicked but hopefully I will learn something! Cost was $17.