I received a lot of info about SAT on this board last year and now I'll be going back for a couple of days. I was too lazy last year to find a great Mexican place - just ate at La Tierra twice and it was decent - but where would the locals go for great carne asado and barbacoa?

Probably to a hole in the wall greasy spoon in a neighborhood that would scare tourists! Kidding , just kidding (kinda)
Seriously, try La Fogata on Vance Jackson for carne asada / fajitas. Try Rosario's just south of downtown - i you though Mi Tierra was decent you will cream your jeans at Rosario's. For a more upscale environment that would remind you of Mexico City try Paloma Blanca on Broadway. Also on Broadway but closer to downtown is Picante Grill - not as lushly decorated but excellent food. La Fonda on Main but NOT any of the other places with La Fonda in their name) is excellent. El Mirador has legendary soups, sort of like a meal in a bowl. Guajillo's is on the edge of Loop 40 at Blanco and serves carnes asadas just like Mexico City (try the tacos al pastor and alambres - to die for!) but the atmosphere is nothing to write home about.
That should tide you over for a couple days!

Rosario's is absolutely wonderful and a quick cab ride from the Riverwalk area if you don't have a car. I live in an area with dozens of authentic Mexican restaurants and have found few that equal Rosario's--nothing fancy but good, fresh food.

Jacala Mexican Restaurant <http://jacala.com/>
606 West Avenue
San Antonio, TX 78201

Phone(210) 732-5222

They are located one block north of Hildebrand on West Avenue. Jacala has been owned and operated by the same family since 1949!

I agree with the Rosario's suggestion. As a matter of fact, my husband had to be downtown today and I asked him to pick me up a Lisa's Special and he got the Carne de Puerco with chile cascavel sauce, and a cerveza.