To subscribe to an iCal published calendar in Hotmail, first log in to your Hotmail calendar and find the ‘Subscribe’ link near the top:
Clicking that takes you to the next screen, which asks for the iCal URL and a name to give your calendar:
Simply paste your iCal URL into the Calendar URL box, and give it a name. Select the color or charm to your liking, and hit ‘Subscribe to calendar’. Your calendar will appear.