Organizing your curriculum around themes is a good way to integrate various subjects. The thematic units listed here are a mixture of global, (ex: systems) topical, (ex: animals) and curricular (ex: weather.)
http://www.uen.org/themepark/
To help you build rich classroom experiences for your students, Utah Education Network has collected resources to support a variety of themes: Exploration, Systems, Home & Habitat, Insects, Cycles , Communication, Patterns, Imagination, and Liberty.
http://emints.more.net/ethemes/index.shtml
eThemes is an extensive database of content-rich, age-appropriate resources organized around specific themes. These resources are created for educators to use in their classrooms.
http://www.stemnet.nf.ca/CITE/complete.htm
This site has extensive Internet resources for primary and elementary students - organized around topical
themes, such as eagles, deserts and zoos.
http://nuttinbutkids.com/themes.htm
Some of the thematic ideas listed here are curricular - and some are not. Most contain songs, art, center ideas
and books.
http://members.aol.com/_ht_a/iteach345/page2/index.htm
This page has lists of links organized so that you can easily find lessons and ideas for specific theme.
http://www.mcps.k12.md.us/curriculum/pep/teach.htm
Don't reinvent the wheel - use these Early Childhood teaching ideas organized by themes.
http://www.atozteacherstuff.com/themes/index.shtml
This page contains over 500 lesson planning resources organized by topical themes