url/web links in ical not working -- what am I doing wrong, if anything?

[Straitsfan]

I'm using ical right now to track my daily activites/to do items, and when i enter a url/web address in the appropriate section, it turns blue, and the i beam pointer changes to a hand. I assumed I could click on it to go to he appropriate site, thinking that it would automatically open up Safari or a new tab/window to take me to the site, but nothing happens, either in an event entry or a to do entry. I also noticed that if I type an email address in either an event or to do section, it doesn't change color at all. Can anyone tell me how to fix these problems? I've looked around in ical preferences, but there's nothing there to change this.