Philosophical theology can be basically divided into three classes: Rationalist theology, Empirical theology, and Intermediate Theology.
Rationalist Theology includes isms such as monism (e.g. Parmenides and Zeno) and non-dualism (Advaitins of India) whose assertions are usually supported by arguments that rationally dismiss experience as false and irrational. This they do with reference to ultimate concepts such as unity, necessity, infinity, immutability, and transcendence (none of which can be predicated of the things of experience). Thus, God becomes the "wholly other" transcendent reality that can only be talked about via negativa.
Empirical Theology, on the other hand, is quite the opposite of the previous. It actually brings religion down to the earth. The gods and goddesses are more human like, and earthly; and, of course, positively understandable in empirical categories. Animism and polytheism are examples of such. In some of them, there is the concept of a Creator who, however, only creates out of pre-existing material. The atheistic religion, Jainism, is more a pluralistic realism in itself and has no place for any special creator God. They retain the idea of the world (including gods, if any) as pluralistic, contingent, finite, mutable, and immanent. Empiricism usually attempts to jettison the rational (e.g. the Logical Positivists attempt to eradicate metaphysics).
Kant tried to bring some union between the two poles.
Intermediate Theology, then would be something that stands at the meeting place of Rationalist Theology and Empirical Theology. The nature of the union may be diverse. I guess we can classify pantheism, panentheism, and probably Buddhist nihilism as the intermediates somewhere between the gods of the mountains (reason) and the gods of the valleys (down to earth experience). Historically speaking, in India, the Buddhist revolt is sandwiched between a very materialistic and Vedic polytheistic age and the Upanishadic non-dualistic age.
A fourth form of theology, however, is Revelational Theology, which doesn't fall in the field of Philosophical Theology, since it is not founded on philosophical arguments (either on rational or empirical) but is based on some kind of "Divine Revelation". Systematic theologians usually use a branch of theology called apologetics to provide arguments for this, a branch which is usually called Natural Theology.
Note: Barth and Brunner usually had referred to Natural Theology as the same as Philosophical Theology (and Barth is noted for calling Natural Theology as demonic.) However, as Mortimer J. Adler has shown, the two are actually distinct. We see that Philosophical Theology usually leads to other conclusions that those affirmed by Revelational Theology.
Note (15 June 2012): John Hick, however, had interpreted Philosophical Theology as the philosophy of the Christian (See quote below from Dialogues in the Philosophy of Religion, 2001, p7):
"these developments, which are technically superb and constitute
impressive philosophical exercises, are however seriously limited, in my
opinion, by very conservative theological presuppositions. They belong
to philosophy of religion in the now old-fashioned sense in which this
is understood to be the philosophy of the Christian (or at most the
Judaeo-Christian) tradition, and they do not face the problems created
by the fact that Christianity is one major world religion among others.
Indeed Alston, Plantinga, Swinburne and the many others who are
working solely within the confines of their own tradition are for the
most part really doing philosophical theology rather than philosophy
Intermediate Theologies usually tend towards either rationalism (where all sense-experience (phenomenal reality) is deemed illusory) or tend towards empiricism (where contingency, plurality, immanence, et al. become important themes).
Follow the complete thread of discussion at Philpapers.