Log into your live.com account, then go to your calendars. Near the top of the page it will say New, Delete, Subscribe, Share. Click on subscribe. This will bring up a page that will ask for a calendar URL. Open a new browser tab and go to the school calendar page, somewhere there should be an ical feed link. If you click on that it will take you to a page with the ical URL. Copy & paste that to the calendar URL space in your live account. You can then name the calendar, choose the calendar color and charm (if you want one). Then click on the subscribe botton at the bottom of the page and your done. It will begin importing the calendar information. If you have the windows live connector loaded to outlook, then the subscribed calendar should show up the next time you open Outlook or hit send/recieve. The outlook connector is a free download (just google it). I've been using it for almost 2 years now with no trouble. It syncs my e-mail, contacts & calendar between my windows live account, outlook & phone (it's a windows phone, not sure if it would work with an iphone).
If you don't have that you can open outlook on your computer, go to the file tab and open account settings. This will open a small box with tabs. Click on the tab that says "internet calendars" and then click new. This will open a box that asks you for the location of the internet calendar that you want to subscribe to. Copy and paste (you'll have to use ctrl v, as right clicking doesn't seem to work) the ical feed URL from the school calendar website here and click add. A settings box opens, there will be a folder name automatically generated, but you can chane that to whatever you want the calendar to be called. Selected your attachement and update limits, then hit enter. Close all other boxes. On the left side of the screen you should see "other calendars" appear. Check this box and your subscribed calendar should show up. If not close outlook and then reopen it. You should be good to go.
I hope this helps and that you could follow the instructions alright. It's harder to explain it in writing, than it is to show someone in person. 🙂