Sale of old house. Income Taxes?, 1031?

[Nate Hundley]

Howdy BP community.  This is my first post.  Hopefully I'm not asking foolish questions!  Let me first say, I'm very interested in getting started in real estate.  Aside from prowling around on forums and listening to podcasts I have no experience.  That said, the questions I have relate more to my primary residence and not really investment properties.  

Here is my situation- I recently purchased a new house.  I didn't have to sell our old house to get the loan for the new place.  This enabled us to move -stress free.  I looked into local rental rates where I live, and it seems to me that keeping my old house as a rental is not a good business decision (unless someone can tell me otherwise).  

On to the actual questions!

Will I have to pay income tax on the sale of the house?  If so, how does this work?  I owe $250K.  I'm hoping to get $330K minus closing costs, but I put $70K down when originally purchased.  I understand you typically don't pay income tax on the sale of a primary residence.  Is there a time period associated with this, if so, how long?  As in, now I own two houses and I'm getting ready to sell one I don't live in anymore a couple months after the purchase of the new house.  If I do have to pay taxes, is a 1031 applicable here?

Thanks any insight!

Nate