At our school we decided that we wanted the web browser to open up to our school's homepage. Several of us have Portaportals (check out www.portaportal.com to set up your own free web-based bookmarks organized the way you want it) that link off of the school's homepage. Mine can be seen at http://guest.portaportal.com/room8
Here are the directions to set each of your students' accounts to set the default page when they open up FireFox on the Linux workstations.
Log into each account and open Firefox from the Applications menu, under the "Internet" heading. When the Firefox window opens, select the "Edit" menu. From the Edit menu choose "Preferences"(at the bottom). A dialog box will open and the "General" tab should be highlighted. In the "Home Page" section type the url of the page that you want to be the home page. Close the dialog box and your home
page is set. Click the home key in the browser window to be sure
I'd like to thank my UMAINE MAT student for figuring out the process and then writing the instructions.