People have had some difficulty getting started with IronPython in VS. Here are suggestions from the VS/PY team on how to make this foolproof:
File->New Project->IronPython Project
Right click Project in Solution Explorer, select Open Folder in Windows Explorer Copy IsisLib.dll to the opened folder Right click the project node, click Add Reference, and then go to the Browse tab. Double click IsisLib.
Open your .py file and add:
For better Python debugging:
Right click the project node
Select Properties->Debug, and change the Launch Mode to Standard Python launcher.