This all changed today because the Sony Ericsson Xperia Arc can now be bought from Sony's US online store. The smartphone comes unlocked, sans carrier branding, and SIM-free. Because of that, the price being asked is a lot more than you're used to if you only check pricing for new two-year contracts. But there's no commitment here. You can use the device on AT&T (on 3G and EDGE) and T-Mobile (EDGE only) for as long as you want.
So how much is it? The Xperia Arc can be yours for $599.99. If you're interested, Sony's store is waiting for you to place your order.
The Sony Ericsson Xperia Arc has a 1 GHz Qualcomm Snapdragon processor, 512 MB of RAM, a 4.2-inch capacitive screen with "mobile Bravia engine", an 8-megapixel Exmor R camera with autofocus and LED flash, 720p HD video recording, HDMI out, Wi-Fi, Bluetooth, GPS, microSD card support, and a 1500 mAh battery. It runs Android 2.3 Gingerbread.
source: Unwired View