I do it with a batch file. This is an extract:
xcopy C:\data\*.* /S /R /y /d:05/18/2004 d:\data
This copies files that have been created or updated on the 18 May from the 'Data' folder on the C:\ drive to the 'Data' folder on the D:\ drive and overwrites any files without prompting.
The above is for Windows 2000 and XP. The command format is slightly different for earlier versions of Windows.
I also use a batch file which opens up the backup batch file for editing and then I use 'Search and Replace' to change the date.