How i can draw a line between two points...e.g.: I have initial point and endpoint and i need trace a line between this points...how i can do that?
Create a polyline feature class or a shapefile, load it into the map, start editing, turn snapping on, draw line from one point to the next, stop editing. Is this what you are asking about?
ArcGIS 10 New Snapping: http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/About_snapping/001t0000003t000000/