Maybe start here. This is a commercial site so remember some of what is said comes with 'commercial' intentions in mind.
http://www.realestateabc.com/homeselling/
It is definitely not a great time to be selling in some US States - mostly those that have experienced the most unsustainable rises in the recent past - so Nevada and parts of Florida would be included, for example. Much depends on where your property is - bit like the UK really.
I don't believe that hardly anyone sells without using a 'realtor agent' - and commissions are much larger than in the UK.