from: http://www.uslegalforms.com/poweratty.htm
A power of attorney can be either general, durable or limited.
FAQs
1) What is a General Power of Attorney?
A General Power of Attorney is a legal document which gives the person you choose (the agent) the power to manage your assets and financial affairs while you are alive. The document must be signed by you (the principal) while you have the required legal capacity to give your agent clear and concise instructions. The appointment may be for a fixed period and can be revoked by you at any time providing you still have the legal capacity to do so. A power of attorney ceases when you die. The executor named in your will then takes over the responsibilities of your estate.
2) What is a Durable Power of Attorney?
A "durable" power of attorney stays valid even if you become unable to handle your own affairs (incapacitated). If you don't specify that you want your power of attorney to be durable, it will automatically end if you later become incapacitated.
3) What is a Limited Power of Attorney?
A limited power of attorney allows the principal to give only specific powers to the agent. The limited power of attorney is used to allow the agent to handle specific matters when the principal is unavailable or unable to do so.
4) Why have a Power of Attorney?
When accidents, sudden illness, planned or unexpected absences occur, or when you just can't cope, you may need someone to manage your financial affairs. It can be done in anticipation of a future need, for a special purpose or for a limited time. The person you appoint is called your agent. The agent will (by your instructions) safeguard and manage your assets and financial affairs if you are unable to manage them for yourself or if you lose legal capacity.
(...)
5) Can a Power of Attorney be revoked?
A Power of Attorney can be revoked by the principal at any time, as long as he or she is competent.