Getting to Yagul without a tour can take some time, patience, and some walking. The bus the plies the road between Oaxaca City and Mitla and onwards passes within 1.5 kilometers from the archeological sight. The walk uphill is not that bad, but it can be dangerous due to the dreaded heat. Take some water with you!
The Ruins of Yagul are amazing! It has the second largest ball court in Meso-America and the largest one in the state of Oaxaca. The largest Ball court is in Chichen-Itza, on the Yucatan Peninsula. Check out my Chichen Itza page!
Yagul is a true gem for those of us who hate over-ranned turist traps. It is located between Mitla and Oaxaca so it makes it a nice stop on your way back to the city. More on the next few tips.
The view from the Mirador is superb, but further up to a higher point lays the best view of Yagul. So don't stop in the Mirador, keep on going a bit further uphill :).