I know I've read it somewhere, but what are the normal and special ranks/titles for priests in the church?

The Lexicanum wiki lists the following

The Ecclesiarchy is not part of the Adeptus Terra, but a wholly separate organisation. At its head is the Ecclesiarch, who, by tradition, is always one of the High Lords of Terra. Below him are the Cardinals, of whom there are several thousand. Below the Cardinals are the Ministorum Priests: Deacons, Pontifices, Confessors, Missionaries and Preachers. Other specialist ranks and duties include Cenobites, Relic-Keepers, and Chapel-Masters.

Also note that there appear to be several 'tiers' of Cardinal - some are referred to when given their full title as 'Cardinal-Astral' - they're the ones with planetary or more-than-planetary dioceses, whilst a 'normal' cardinal might be the ecclesiarchal head of a hive city.

Deacons are priests but often priest-administrator or aids to someone superior, running the Ecclesiarchy's 'civil service' - a good example is Mammon, who's more or less directly responsible for the Vraks war.