There was some confusion yesterday over the comment I made on the intermediate state in the NT Wright post and whether it is Reformed. Let me assure you that it is. Not only is it Reformed but it’s biblical (of course — why would it be Reformed if it wasn’t biblical 🙂 It is the state between death and the resurrection, when body and soul are separated by death. The soul goes to heaven and enters the presence of Christ.
According to Louis Berkhof:

The usual position of the Reformed Churches is that the souls of believers immediately after death enter upon the glories of heaven. In answer to the question, “What comfort does the resurrection of the body afford thee?” A. “That not only my soul after this life shall be immediately taken up to Christ its head; but also, that this my body, being raised by the power of Christ, shall be reunited with my soul, and made like unto the glorious body of Christ.” The Westminster Confession speaks in the same spirit, when it says that, at death, “The souls of the righteous, being then made perfect in holiness, are received into the highest heavens, where they behold the face of God, in light and glory, waiting for the full redemption of their bodies.” Similarly, the Second Helvetic Confession declares: “We believe that the faithful, after bodily death, go directly unto Christ.” (pg. 679)

This doctrine is supported by:

ESV 2 Corinthians 5:8 Yes, we are of good courage, and we would rather be away from the body and at home with the Lord.
ESV Philippians 1:23 I am hard pressed between the two. My desire is to depart and be with Christ, for that is far better.
ESV Luke 23:43 And he said to him, “Truly, I say to you, today you will be with me in Paradise.”

This intermediate state in heaven is meant for those who are united with Christ (believers). The intermediate state between death and the resurrection is hell for the unrighteous. According to the Westminster Confession:

And the souls of the wicked are cast into hell, where they remain in torments and utter darkness, reserved to the judgment of the great day. Beside these two places, for souls separated from their bodies, the Scripture acknowledges none.

And from the Second Helvetic Confession

We believe that unbelievers are immediately cast into hell from which no exit is opened for the wicked by any services of the living.

The biblical support for this is Luke 16.