There are a few REALLY good sites out there with detailed Orff lesson plans, etc. This is by no means a conclusive list, just a start:
Ontario Music Educator's Site:
This is a site I wandered onto and it has some really good info/lessons/etc.
Utah Schools site:
Complete with sound files, etc. http://www.schools.utah.gov/curr/fineart/core_curriculum/general/songbook.htm
For all you "techies" out there; this is an ipad app called, appropriately, "Singing Fingers: This app lets your finger ‘paint’ sound. Play it back by moving your finger(s) over the shapes and swirls. This could be used for graphic scoring, solfa acivities and even composition tasks in groups.
Add your own in the comments.