Yes. With the Edge 305 you have to manually create the route by drawing it on the map and then placing turn directions at each turn you want to signal. Some 3rd party software helps this process go a little faster, like bikeroutetoaster.
I've never actually done it because it's a little cumbersome and I tend to ride well known routes with people I know. I mostly use the Edge as a sampling computer to plot HR/cadence/speed over distance/time/elevation.