Copy the iCal URL from the Browser and email to your email id which is configured on your iPhone.
After the iCal URL is received on you iPhone click on the link. Ensure that the webcall:\\ is replaced suitably with http:\\ or https:\\ in accordance with whether your Web TimeSheet application is setup with secure browsing or not.
After you click on the link it gives you an option to sync the link, select the sync option.
After this step all Time Off entries will be synced in your iPhone Calendar.