To help kick off the campaign, CatholicVote.org has released this outstanding short video:
Catholic Vote also has an excellent blog which can be found here.
A short essay that provides a succinct and powerful explanation of the Church's teaching on contraception can be found here.
A commentary on why the Catholic Church opposes contraception can be found here.
Full text of Pope Paul VI's prophetic Humanae Vitae can be found here.
Information on the benefits of Natural Family Planning can be found here.