Bruce is entirely right: there are technical issues including SemanticImport and SemanticImportString in either WPC as provided or with the Desktop upgrade. We're certainly glad to know about your interest in SemanticImport for the Desktop product and will take that into account in prioritizing further development in this area. Both of these functions will certainly be available in the next edition of Mathematica as well as other new products.
SemanticImport and SemanticImportString do take documents and strings, respectively, and annotate them with semantic structures similar to W|A. However, the scope of SemanticImport is narrower than SemanticInterpretation, which attempts to interpret inputs broadly, but instead is optimized for structures typically found in spreadsheets and tabular data, such as dates, amounts of money, countries, and states (see the SemanticImport documentation for a complete list). However, SemanticImport does take specifications to use any kind of Interpreter if expected. Overall, SemanticImport and SemanticImportString represent good tools for a first-pass over sets of data, which can be enriched with Interpreter and SemanticInterpretation in further processing.
I hope this helps.