How do I calculate the social security taxes that are being withheld out of my paycheck?

First its not a good idea to piggyback your question on someone else's. This can lead to confusion. You should start a new thread. So I've moved your question to its own thread.

This site may help:

Tax Withholding Tables (http://www.irs.gov/newsroom/article/0,,id=109817,00.html)