Google Refine

Google Refine is a power tool for working with messy data, cleaning it up, transforming it from one format into another, extending it with web services, and linking it to databases like Freebase.

The RDF Extension for Google Refine adds a graphical user interface(GUI) for exporting data of Google Refine projects in RDF format. The export is based on mapping the data to a template graph using the GUI.

The article Transforming Spreadsheets into SKOS with Google Refine provides an example of transforming xls spreadsheets into RDF.