batch file to copy based on specific creation date

Hi I am try to learn some simple things in batch files. Even though I have solved the majority of my "problems" I am still having some. Does any one can tell my how to write a batch which is going to read some folder and then to copy a number of files based on their creation date to some other folder? .For example all the files look like:090121.gz. So what I need is to read the filename and if it is contain the appropriate day to copy it in a new folder. Thnks all of you