I know this has been answered, but here is another way to do this, just in case someone else in the future needs it. %DATE% is already set in the OS and will give you a date like Thu 05/26/2005. Try going to a command prompt and type ECHO %DATE% and it will show todays date. You can just get parts of the date by using the colon and tilday. %DATE:~0,3% will show you the first 3 characters of %DATE%. That's what the 0,3 does. Starts at spot 0 (zero) and shows the next 3 characters (this will include spaces) So, %DATE:~0,3% translates to "Wed". If you want just the date, you would use %DATE:~4,10%. This will show you the mm/dd/yyyy. Because you can't have slashes in a file name, you would have to grab parts of %DATE% and put them together. To get the date without slashes, you can use
ECHO %DATE:~4,2%%DATE:~7,2%%DATE:~10,4%
This translates to 05262005 (todays date as I type this)
To explain this, there are 3 parts...
%DATE:~4,2% gives the "05"
%DATE:~7,2% gives the "26"
%DATE:~10,4% gives the 2005
So, to change, say, a file named "today.txt" to 05262005.txt you would type...
REN today.txt %DATE:~4,2%%DATE:~7,2%%DATE:~10,4%.txt
This is probably a longer explanation than was needed, but just in case someone in the future could use it, there you go.