Taxes - 2 Part question

I am 62 and retired but not drawing social security yet.

 

Is there a tax credit or deduction when selling and buying a house?  I am downsizing from my current house to a smaller less expensive house.

 

What are the tax ramifications if I buy a new house with money from my IRA while still living in my current house.  The current house will be sold after the new house is ready.