I just bought a Syil X3 milling machine with the Mach 3 software.  I would like know what is the best software (Meaning user friendly) I can buy/use to help me create G-code, both 2D & 3D.  I have drawings in AutoCAD so it would be easier for me to convert them, or I can just re-draw them in the new software program.  Please let me know your advice to me.

Thanks. 

your 2D drawings can be done with LazyCAM, that is included with Mach3, all you have to do is export the drawing from Autocad as a DXF file and lazycam will make gcode from it.  As for 3D its a mine field, what is easy for one is not always so for another.  Best thing is to down load some demo's and have a go.  look at Bobcad, Rhino, Alphacam, mastercam, and onecnc, price will probably dictate your end result.

Graham.