Application to help delete unwanted programs?

I've got a MacBook Pro (OS 10.5.8), and over the last 6 months I've downloaded a number of demos (music software) and would like to delete them and their associated files. For applications that don't have an Uninstaller, is there a program (freeware?) that I can download that will locate these additional files and delete them? Or make them available for me to manually delete?

Thanks in advance.