Well, UK retailer Clove has the 3G-enabled Acer ICONIA TAB A501 in stock and ready to ship. Unfortunately, it comes with a rather steep price tag of roughly $850, which seems like a bit too much for what you are getting, namely a dual-core Tegra 2 chipset, 10.1-inch display with 1280 by 800 resolution, 32 gigabytes of storage, and Android 3.0 Honeycomb running the show. The ICONIA TAB A501 also packs a 5-megapixel main and a 2-megapixel front-facing camera, GPS, Wi-Fi, Bluetooth, and a standard size USB 2.0 port.
If you have your mind on the Acer ICONIA TAB A501 and the lack of 3G is not a dealbreaker for you, the nearly identical, Wi-Fi-only ICONIA TAB A500 is available at Best Buy for as low as $450. On the other hand, if you absolutely insist on being connected to the Internet at all times, just sit tight and be patient as AT&T and Verizon are expected to have the tablet on their shelves sometimes soon.