Outlook users: have you ever sent an email which was supposed to have an attachment, but didn’t attach the file? Of course you have. To help prevent this in the future, check out the free Outlook plugin: Missing Attachment PowerToy.

This free PowerToy for Microsoft Outlook is designed to help you avoid that exact scenario, helping you save time and avoid needless embarrassment: When the Missing Attachment PowerToy detects an outbound e-mail message containing words which you typically use when including attachments, it will offer you an opportunity to revise the e-mail before Outlook sends it on its way!

Not too much else to add here. You can customize the words the tool scans for before sending to fit your typical verbiage, so there is flexibility. One important note though is it only works with Outlook 2007.