Yeah the soundtrack for Amores Perros is excelent. I bought it too cause it was impressive. I especially loved the songs inspired by the movie. They feature some of not only Mexico's but the rest of Latin America's best artists like Ely Guerra, Cafe Tacuva, Bersuit Bergarat, Julieta Venegas, and even Celia Cruz!
If you liked that soundtrack, I also recommend the soundtrack for Sex, Shame, & Tears (Sexo, Pudor, y Lagrimas). The title song by Aleks Syntek....very good!