6zap
Description: 6zap is a full-featured, open source communications platform that integrates e-mail, calendar and contacts functionality into a single page. Built with Web 2.0 technologies as a foundation, 6zap is intuitive and easy to use. It enables users to simply switch back and forth between applications, returning to the last message, contact or calendar entry they viewed.
Features:
- 10GB Storage
- 10MB Attachment Limit
- IMAP support
Signup: http://www.6zap.com