If you go into iTunes and click CTLR+, (that's Control key and the comma key together). Click on the Devices Tab, then you can click on a backup you want to delete, and select delete, all gone.
Hi Pocobear, I did exactly what you suggested; it only shows one backup from "yesterday".
I thought a folder in Explorer had been identified where all of the backups are stored and if you didn't clean it out a lot of data was being unnecessarily saved.