How can I import email addresses from a Microsoft Excel spreadsheet into MMM?

MMM lets you "import" plain-text files only. Microsoft Excel spreadsheet is a binary file actualy that can not be imported into MMM directly. However you can easily convert it into a plain-text file by using the File - SaveAs command from the main menu of Microsoft Excel. After you open the Save dialog box in Microsoft Excel, you should select the Save as type as Text (Comma delimited text), enter the file name then click the Save button. When the plain-text file is ready, all you need to do this to open NotePad, select all and copy text to clipboard. Go to MMM and paste (Ctrl+V) above "List of emails to send" memo.