The maximum size for an email attachment is approximately 30 MBytes of files. The following article explains how to send larger attachments without negatively effecting your recipients.
PSMail protects the security of your emails throught the TLS (Transport Layer Security) protocol called Secure Socket Layer (SSL). The following article explains what SSL is and how it works.
The importance of a secure email service.
The basics on email, its uses, and its security.
This article contains a comprehensive list of questions and answers concerning SPAM and how your PSMail account can help you deal with it.