Samarqand is a city in southern Uzbekistan.
There is a bus station at the end of Registan street (a bit further, after the last crossroads actually). Take a minibus to the border control point 30 km away from the city to avoid losing a lot of time with short local rides.
West towards Buchara
Take bus 35 to the final stop. You will be at the roundabout where the road going out of town converges with the ringroad. Therefore you will be able to catch long distance trucks going around Samarqand. Hitch-hike just past the roundabout.