How trained are the elders in the Jehovah's Witness denomination?

Jehovah's Witnesses are known to have no pastors or priests, because having pastors or priests would go against their theology. Instead, they have "elders". From an outsider's perspective, elders appear to function in the same way as the priests or pastors from other Christian denominations, namely because these elders do not include women. Women, however, are allowed and encouraged to become ministers and preach the gospel door to door. What are the requirements for a person to become an elder? What type of training do elders have? And have elders ever been formally trained in Christian history, biblical studies, or theology? A related question: are Jehovah's Witnesses allowed to read a mainstream, scholarly bible?