The new iPhone 4 is available for pre-order today in the Apple Store. The Apple Store is already under heavy load and the one in the UK is again down for maintenance right now.
If you get in, you also can purchase the first official iPhone 4 accessories on the Apple Store.
The iPhone 4 accessories offered by Apple include iPhone 4 Bumpers in various colors selling for $29 and shipping on July 2nd.
The iPhone 4 Dock sells also for $29 and ships July 2nd. The Apple iPhone 4 Universal Dock Adapter sells for $9.
More details on the Apple Store.