Check your fertilizer levels. I grow tomatoes every year in Louisiana with no issue but this year I have a few "wilty" ones. When I check the fertilizer level, I had over fertilized in that area (easybloom confirmed it).

Great idea! Have it with wireless capabilities (like to an access point) and be able to get info from it - or better yet - have it send the info directly to my account online using my WAP and internet service.