Teachnology is a great resource for teachers. In particular you can peruse their library of Spanish lesson plans for teachers.
I really like the Spanish Lesson Plan titled: Contents of My Backpack. It is a great hands on lesson for exposing students to classroom vocabulary in Spanish and having your students practice with it. It could easily be tailored to any foreign language or ESL class.
If you need some fresh ideas for your high school Spanish lesson plans or elementary Spanish lesson plans this is worth a look. You can read and print the lesson plans for free.
Teach them Spanish is another great resource! I think I have 4 levels of this book. These are a perfect supplement for middle school Spanish and High school Spanish level I as well as being a great resource for elementary Spanish. At less than $10 for a reproducible book these are quite the bargain (imho) !
Do you know of some great resources for Spanish Lesson Plans? Leave your ideas in the comment section.