This app was mentioned in 1 comment, with an average of 1.00 upvote
This app https://play.google.com/store/apps/details?id=com.plasticitylabs.android&hl=en
is for android, iphone, and blackberry. You can enter your mood multiple times a day and it makes a graph for you over time. I know businesses use it, I think individuals can use it too...? Look into it. Pretty good app.