You can't go wrong with this one..the best free curves plugin for Elements, I reccomend it to all my students.and belive I put a link to it before in this forum
http://free.pages.at/easyfilter/curves.html
crafty
PS I would also recomend this for Elements for as it will save you having to use a clipping layer to accomplish the same thing.
http://graphicssoft.about.com/od/pse...layermasks.htm