Copy and paste this fragment at the end of your elasticsearch.yml file. If you're on mac, and installed elasticsearch using brew, this configuration should be at /usr/local/Cellar/elasticsearch/0.19.10/config/elasticsearch.yml

elasticsearch_spanish_analyzer.yml

index: 
  analysis:
    analyzer:
      spa:
        type: custom
        tokenizer: standard
        filter: [standard, asciifolding, lowercase, stop, snow_spa]
      default:
        type: custom
        tokenizer: standard
        filter: [standard, asciifolding, lowercase, stop, snow_spa]
    filter:
      snow_spa:
        type: snowball
        language: Spanish