Put the SASL passwd in /usr/local/etc/postfix/sasl_passwd:

kanga.honeypot.net      woozle:[whatever]

Modify main.cf:

myhostname = woozle.honeypot.net
inet_interfaces = localhost
relayhost = kanga.honeypot.net

smtp_sasl_mechanism_filter = !gssapi, !external, static:all
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/usr/local/etc/postfix/sasl_passwd
smtp_tls_note_starttls_offer = yes
smtp_tls_CApath = /etc/ssl/certs
smtp_use_tls = yes

-- KirkStrauser - 13 Aug 2006