What do I need know before withdrawing from a Roth IRA?

I am 54 years old. I wish to cash in my roth ira. What penalties or taxes will I pay?

How do I determine the basis for my roth after a partial distribution has been made?

I purchased a roth ira in 2006. It is now worth only 85% of the original purchase price. Can I withdraw the remaining principal without penalty although I am less than 59-1/2?

Will be 60 yrs old next month. Request maximum Roth IRA contribution allowed for years 2008, 2009 & 2010.

We want to use funds in a roth ira for closing costs on a house but need to leave them in the bank until after closing per the mortgage company, can i still withdrawl funds after closing with no penalty?