There are several web services that will notify you if a web page changes.
One of these is www.changedetection.com.
You need to sign up, but the service is free. Once singed up, you enter the URL of a page you want to monitor. There are various options to select, but, by default, it will check the web page once a day and send you an email if it sees any changes. Alternatively, it can send the alert to your RSS feed.
When ChangeDetection sends you an alert, it will give you the URL of the web page it's monitoring and a link to the ChangeDetection change log for that page. The change log shows the last 30 changes it has detected, so you can look back at previous changes. Text that has been deleted is shown like this and new text is highlighted in yellow so you can see exactly what's changed.
ChangeDetection can also compare two web pages for you and show you what's been added and what's been deleted.