Data Wrangler is a web-based service from Stanford University’s Visualization Group. Similar to Google Refine it allows interactive cleansing and transformation of messy, real-world data for further analysis in e.g. Excel, R, Protovis etc.
To learn how to use Wrangler read this research paper or this blog post.
Wrangler is still in its alpha version so if you want to give feedback to the developers, just go for it.
Wrangler Demo Video from Stanford Visualization Group on Vimeo.
Data Mining World 