http://www.angelfire.com/space/thegospeltruth/trinity/verses/2Cor3_17.html

Apostle Paul vs. Trinitarian Apologists
Trinity doctrine: Jesus IS NOT the Spirit
Bible: The risen Jesus IS the Spirit.

In Trinitarianism, Jesus is NOT the Spirit. But the Bible says that the risen Jesus is "life-giving Spirit." (1 Corinthians 15:45). Remember that for us Christians we receive only "one Spirit" (Eph 4:4) which gives us life. Notice that Paul is telling us how the Spirit gives life in this passage (2 Cor 3:6). The risen Lord is that Spirit, life-giving Spirit.