I recently did a video on how to use Talend Open Studio to import data into Salesforce.com. One of the missing features in the video was transforming data via lookups. Luckily Ward Loving just posted a fantastictutorial on the Appirio Tech Blog showing how to do lookups to other input files or databases while performing transformations on your data with basic Java expressions.
You can read the entire article on the Appirio Tech Blog.
