I've installed sSMTP on Ubuntu 10.04 via:

sudo apt-get install ssmtp

My configuration file is:

#
# Config file for sSMTP sendmail
#
# The person who gets all mail for userids < 1000
# Make this empty to disable rewriting.
[email protected]

# The place where the mail goes. The actual machine name is required no
# MX records are consulted. Commonly mailhosts are named mail.domain.com
mailhub=smtp.gmail.com:587

# Where will the mail seem to come from?
#rewriteDomain=

# The full hostname
hostname=somedomain.com

# Are users allowed to set their own From: address?
# YES - Allow the user to specify their own From: address
# NO - Use the system generated From: address
#FromLineOverride=YES

[email protected]
authpass=****
usestarttls=yes

Am I transmitting my credentials in clear text? Is calling ssmtp a secure operation?

Thanks.