We just released an official 1.0 of the MLS module for Drupal!
After many months of development it's finally here. This module gracefully works with VieleRETS to integrate RETS-based real estate listing feeds with Drupal. It also includes an API for developers to write the one-off scripts necessary to handle IDX-based real estate feeds.
The module can handle multiple feeds and includes cron scripts to update listings automatically. Each listing gets created as its own 'MLS Listing' node and is fully searchable. Fields for each listing are fully customizable via CCK and can be easily mapped to the fields returned by each individual MLS feed. It is also possible to augment data returned from MLS feeds with your own (please check the service agreement with your MLS provider first).