I help my neighbor break out 420 acres of CRP in the fall of 2007.  We went over it twice with JD chisel plows and spikes.  Each plow how Flexicoil tines harrows mounted on the back of the plow.  Once going around and once at an angle in each field.  He then took our JD 375 disk and went over it once with that.  Next spring we put 16" shovels on the plows and plowed each field twice before seeding.  The last time over it we both had Flexi Coil packers behind the plows which really made for a nice seedbed.  Spraying everything out like others suggest would be the quickest and least erosive way.  But sometimes that don't work completely, or you have bunch gopher holes that need to be level out or you can't do it like if you were an organic farmer.  We used to break sod and alfalfa like I described earlier but we started spraying everything instead of plowing.