According to another Samsung Illusion owner's post in samsungillusionforum.com, you can get notifications from Facebook by adding your Facebook account in your phone's Accounts & sync. source

To add your Facebook account:
1. From the Home screen, press the Menu Key, then touch Settings ➔ Accounts & sync ➔ Add account ➔ Facebook.
2. Enter your Email and Password, then touch Log in.
3. Follow the prompts to complete the setup.