As expected, Sprint's first WiMAX compatible smartphone, the HTC EVO 4G, has entered pre-order season (in Best Buy retail stores only) and will make its official debut on June 4. The much-anticipated device will be priced at $200 with a new 2-year contract, which will set you back a minimum of $70 per month with Sprint's "Everything Data Plan," as well as an additional $10 per month for WiMAX coverage.

This additional charge will be mandatory for all HTC EVO users, regardless of whether they live in a WiMAX coverage area or not, but it will give them true unlimited data instead of the 5GB limit on regular plans. The so-called 4G service sees average downloads of 6Mbps and is available in 32 cities in the US – Sprint intends to cover 80 major markets by the end of 2010. Where WiMAX connectivity isn't available, the smartphone will fall back to Sprint's EV-DO network.

The HTC EVO has attracted a lot of attention with its high-end feature set, which includes a large 4.3-inch screen, 1Ghz Snapdragon processor, 512MB of RAM, and two cameras (an 8-megapixel flash-equipped camera capable of 720p video and a 1.3-megapixel front facing camera for video conferencing). It also includes the ability to share the WiMAX connection with up to eight other devices via Wi-Fi, but unfortunately Sprint will charge an extra $30 for this.