"There's no way to set the ringtone individually for different types of notifications (e.g., new gmail, new text, etc.) There's just one ringtone selection to rule them all."

I just found a way to do this for gmail and text messages. It's about the same for both.

1. Go into the main Messaging or GMail screen


2. Click the menu icon (the one between back and home)


3. Click "Settings"


4. Scroll down to "Notification Settings" and select the desired options (like "Vibrate").