Add 'S' For Safety
Practically all of Google's services can be accessed via HTTPS, which makes for a totally secure connection across the Internet--the same kind of connection online banks use. Just add an "S" to the http:// part of the address to make https://. For example, to view the Microsoft Word file mentioned above over a secure connection, you could type the following:
https://docs.google.com/viewer?url=http://keirthomas.com/dump/testfile.docx
Gmail can be configured to use HTTPS always by clicking the Settings link at the top right, and then selecting Always use HTTPS under the Browser Connection heading that appears.