1. There are many DNA polymerases in the human cell (see http://en.wikipedia.org/wiki/DNA_polymerase). Which one(s) are you asking about?

2. DNA polymerases are often multi-protein complexes; each polypeptide chain is produced separately, and then they associate in the cell to form an active enzyme. In humans, I believe the final enzymes that perform the bulk of leading strand (Pol epsilon) and lagging strand (Pol delta) synthesis during replication are only fully assembled when they are are actively replicating DNA.

3. *Where*: Like other eukaryotic, protein-coding genes, DNA polymerase genes are transcribed *in the nucleus* by DNA-directed RNA-polymerase II into a pre-messenger RNA which is then processed into a mature messenger RNA; the mature messenger RNAs are transported to the *cytoplasm*, where they are translated into polypeptide chains. Either the individual proteins or the protein complex(es) that assemble to form the active DNA polymerase, which acts in the nucleus, must enter the nucleus.

4. *When*: It is likely that DNA polymerases are synthesized shortly (minutes to hours) before they are used. Those that are used for bulk replication (polymerase alpha, delta, and epsilon) are required in the S phase of the cell cycle, however I believe the polymerases that are active in DNA repair are present throughout the cell cycle.