There are many advantages to having a CD. By having a CD, the interest rate of return is much higher than in a savings account or banking account, usually up to 15x's as much. Right now is not a good time for CD's though as the interest rates are low because of the economy.
The advantages of putting your money in a cd. one you will not be able to touch it for at least six months if you do there will be a penalty. Two you will have the chance to roll the cd over again when the time period for the cd is up. You also have a chance to transfer the cd to another account you have with that bank when it matures
Only if it is short time. You will earn little but it is completely safe. Inflation is coming so be prepared to roll it over into a new better rate. Perhaps, take them six to 12 months at a time so you aren't stuck in a low rate.