Secular Humanism is about using reason, ethics, and social justice and rejecting dogma and superstition.

Universal ethics should be practised and taught in schools. To this extent, Christian ethics will be practised and taught in schools, as will Jewish, Muslim, Buddhist and even secular ethics - they all mean the same thing. But Christian teachings belong in Christian institutions and Scripture classes.

MICHAEL B. GILL has written:

'BRITISH MORALISTS ON HUMAN NATURE AND THE BIRTH OF SECULAR ETHICS'

It's been argued that libraries are secular churches. If you're looking for more instruction (and don't want to harass the librarian), Unitarian services are a good choice. Another option would be to see if your local community college offers any courses on ethics, or ask a University professor if you can sit in and audit a class.
You may also want to check out Secular Humanism http://www.americanhumanist.org/ .

The largest difference is obviously that secular humanism is a philosophy, while Christianity is a dogmatic religion.

Secular humanism focuses upon humans for cultivating morality; Christianity teaches that God is responsible for man's morality and free will.

Secular humanism wishes to transcend boundaries of dogma and parochial loyalties based on race, religion, gender, sexual orientation, or ethnicity.

Furthermore, secular humanist ethics/morals are subject to criticism and rational guidance, unlike dogmatic, unquestionable, god-inspired tenets of Christianity.