How to disable notification badges for the iPhone Mail app (iOS4)?

What I've done is disable "Push" for Mail. That way, I only get new mail when I go into the Mail app and refresh it. It saves on both distractions and battery life.

In Settings > Mail, Contacts, Calendars > Fetch New Data, I set Push to Off and the frequency to Manually.

Turning on/off badges/alerts/sounds notification for each app is now available in the main settings on iOS 4.

However, this is only for 3rd party apps. Turning off badge notification for the Mail app is not possible at the moment.

It's possible only on iOS 5. Notifications → Mail and toggle "Badge App Icon".