Yes, there is a tax credit for having children. You can claim your child or children as dependents on your takes until he or she is eighteen years of age.
As long as your baby was born before Jan 1 (2010 for this year) and on December 30 (2009), the baby is a tax credit. Since the baby is already 2 weeks old -- you have the tax credit.
You wiil be able to claim your baby on this year's taxes. Be sure to get a Social Security number as soon as possible if you have not already filed paperwork for it.
Any child born on or before December 31 of the tax year is counted as a dependent for that entire tax year; there is a standard deduction for each dependent.