Email Web Part Standard Edition Features:

• Send e-mail directly from SharePoint site
• Add actions to send e-mail directly from List Item
• Auto-populated To, Subject and body with item column values
• Customizable e-mail From and Reply To fields
• Supports custom SMTP settings
• Supports Active Directory users, SharePoint users, SharePoint groups, Distribution Lists as e-mail recipients
• Supports direct e-mail addresses
• Ability to expand distribution lists and send e-mail directly to its members
• Supports e-mail templates
• Permissions management (restrict users to send e-mails)
• User friendly UI (Microsoft Outlook like pickers for To, Cc, Bcc e-mail boxes, html message editor)
• Language pack support (desired localization could be added by request)

Email Web Part Professional Edition Adds:

• Ability to attach files from SharePoint Web site to e-mail
• Ability to attach files from local disk
• Option to automatically attach current document or list item Attachments

Email Web Part Enterprise Edition Adds:

• Ability to store outgoing e-mails in SharePoint lists
• Ability to send email selecting multiple items
• Supports selection of e-mail recipients from other SharePoint list