At the Samsung/AT&T event today, the Samsung Infuse 4G was officially announced, and slated to be available May 15th. Our hands-on is here. It was also called the "first phone to support hspa+/hsupa at launch”. It has a dual antenna, just like the Motorola Atrix, but unlike the Atrix, it will have HSUPA enabled at launch. 4G comes in many different flavors, not all created equally. Read on for more details.