Salesforce Query is a module that allows Drupal administrators to define semi-arbitrary queries that may be run against a connected Salesforce instance. Once a query has been defined, it may be called either internally from another Drupal module, or externally via an automatically generated web service.
Currently functioning query types include SELECT, CREATE, DELETE, UPDATE, and FIELDINFO (which returns Salesforce field definitions.)
The queries themselves are built using a convenient graphical frontend. A query can only be built by expressly permitted users. The queries are also tightly controlled - only specified users (or roles) may call a query.
This module is useful for building process flows between Drupal and Salesforce.
Salesforce Query is hosted on Drupal.org as a Sandbox module. Feel free to download it and try it out.