Make notifications/messages fill the screen Is there a way to have it so notifications/messages fill the screen, so I can't help but notice them when I pick my phone up?

Using an LG-Ally
SMS Popup will create a modal dialog box on your screen when you receive a text message.  You can make it turn the screen on too if the phone's screen is off.

Handcent (full SMS replacement app) also has a similar feature built into it.