Cleaning up old files

I have a huge, shared directory (70gb) with files (mostly documents) from the beginning of our network on it. I need to clean it up. I'd like to move all files within a specific date range to another directory, creating the subdirectories on the fly. It's too big a job to do manually. I don't know how to write a script or batch file to do this. Does anyone know of a utility that I could use? I could probably modify a script or batch file, but I'm too pressed for time & rusty to write one from scratch.

Thanks for any help.