Edit
Preferences
General tab
File type: Attached E-mail
Location: D:\ACT6\Email\Attached\2006
Set one up every year to keep the number of files in a folder manageable.
This will not change the folder for emails already stored, for
example.
D:\ACT6\Email\Attached\2005
D:\ACT6\Email\Attached\2004
D:\ACT6\Email\Attached\2003
etc.
If you need to move files from folder to folder, you can use ACT! Attachment Freedom