Cyber-D's Autodelete can delete old files in a folder (and subfolders) you selected. Simply select the folder you wish to clean (downloads for example), set the rules (older than 30 days since created) and how to delete (move, recycle, secure delete). The cleanup is done on system startup only so it does not stay open in the background or you can run the cleanup manually. Log files are created per clean session and filters can be applied. Cleaning status window, run on startup and log files can be disabled if you wish.
If you are not satisfied with Autodelete, then you might want to give Belvedere a try. I did not make Belvedere myself, but it can also do what Autodelete does and more.
Cyber-D's Autodelete is also featured on PCWorld.
If you get an "Error 5:" message when autodelete runs, then you most probably are a Windows Vista user and have UAC (User Account Control) turned on. The only way to run autodelete with UAC on is by running it as an administrator. You can also right-click on the autodelete shortcut and go to the 'advanced' tab, then the 'advanced' button and activate 'run as administrator'. The program will not give an error but you will get a UAC warning every time the program runs. I have not found a way to avoid this, so the only advice I can give is to disable UAC by going to the control panel and in the search type 'disable UAC', you will be given a link to disable UAC.
You can also avoid UAC prompts by ising Microsoft’s Compatibility Toolkit. Read more about it here: http://www.ghacks.net/2010/07/08/get-rid-of-uac-prompts-with-microsofts-application-compatibility-toolkit/