This link answers your question succinctly.
(text from link)
"Beginning with SolidWorks 2003, Inventor R5 files could be opened directly. As of SolidWorks 2011, Autodesk Inventor R11 part (.ipt) and assembly (.iam) files can be imported. Drawings can be imported if first saved as DXF/DWG, which loses associativity to the 3D model.
The feature history of parts can be imported if Inventor is installed on the same system. Inventor View can be used to import parts as solid bodies.
SolidWorks can import the following Inventor features: chamfer, draft, extrude, cut extrude, extrude/revolve with contour selection, fillet, holes, linear and circular patterns, mirror, reference geometry, revolve, cut revolve, shell, sketch, sketch dimensions, sweep, cut sweep, threads. Unrecognized features are imported as solid bodies."
1. You can download and install a 30 day trial of Inventor from the Autodesk website.
2. Once Inventor is installed, you can open .ipt files and have them rebuilt as native SW models. Why does this work? Because SW remotely controls Inventor through Windows DDE to read the .ipt history tree, query the feature data, and then builds in a .sldprt with the same type of feature in at the same coordinates. Whole .iams can be converted, although I've had spotty results and have had to go back and re-run some individual .ipts and substitute the converted files in the finished .sldasm.
3. Solidworks will not open Inventor .idw (drawings).
4. I can't speak from experience as to how well or even if iProperties are translated over. It wasn't a concern for me at the time.