Retirement

If you were born after 1959, you will have to wait until you are 67 years old before you can collect your full benefits. This current rule may not stay the same for the next 30 years. You should start planning for your retirement without relying on Social Security as soon as possible.

You will need to file form SS-5. Contact your local Social Security office or go on the Internet http://www.ssa.gov/ssnumber/ and download the form.
If you are expecting a child to be born this year, keep in mind that you will not be able to take a deduction for your new baby without the social security number.
Most hospitals are aware of this and provide the forms along with birth records.

If your combined wages from both jobs exceed $110,100 for the current year and more than $4624.20 was withheld, you are entitled to receive credit for the excess social security paid.
That amount is taken as additional federal withholding on IRS Form 1040, page 2 when you file your tax return and can be refunded.

Yes, but only if your son or daughter has "earned income" (not investment income) which is reported on their tax return. The contribution is limited to the lesser of $5,500 or net earned income after deducting expenses related to the production of those earnings. A fast food employee, paper route, or other part-time jobs are examples of earned income sources.