forfiles – a resource kit tool that iterates files in a folder, can do it on date, and let you then run a command
You can get it here: ftp://ftp.microsoft.com/ResKit/y2kfix/x86/
This command should (I haven’t tested it myself) delete all files older than 30 days, under c:\temp and recurse into subdirectories.
forfiles /p "C:\temp" /s /m *.* /d -30 /c "cmd /c del @path"