The ad says that the HTC EVO will be available for pre-order later this month, which obviously means that Sprint stores will be carrying the EVO as well at that time.  Apple (AAPL) is widely expected to announce its 4th generation iPhone  at its Worldwide Developer Conference at the beginning of June and ship it a month later.  Any head start that Sprint/HTC can get on Apple will be beneficial.

The Sprint EVO 4G  is the next king of the hill Android phone.   Besides having a 4.3-inch screen and 720P HD video capture and playback via HDMI interface, it is also a 4G (where available) mobile hotspot.  That means you can throw away your Mifi and don’t have to plunk down any extra money for an iPad 3G data plan with this product.  All of your (and family and friends’) wireless data needs can be met by this device, which allows up to 8 devices to share wireless data. Some people may even consider giving up their home broadband connections.

The question on everyone’s minds is: how much is this thing going to cost and will Sprint (S) include the mobile hotspot service like Verizon (VZ) does with its Palm line, or will there be an additional tethering charge added to the bill.

If Sprint can somehow keep the monthly payments near where Verizon has its Palm Pre+Mifi plans, it should have a hit on its hands.

In practice, the 4G service that Sprint and Clear provide has gotten mixed reviews.  While it is faster than 3G when working, it has a much smaller nationwide footprint, and reports say that it doesn’t work inside buildings as well as previous generation wireless services.

The good news is that the EVO will step down to 3G when a 4G signal isn’t available.  Also, unlike other CDMA phones, it can use 4G data while on a 3G network phone call.

Some of the more impressive specs of the HTC EVO:

• 4.3-inch, 800×480 TFT touchscreen (current iPhone 3GS is 3.5 inch 320×480)
• 1 GHz Qualcomm Snapdragon processor
• Dual 3G/4G WiMAX connectivity
• MicroSD card slot (up to 32GB), USB
• Forward-facing 1.3 megapixel camera
• Rear-facing 8 megapixel camera with auto-focus and 720p HD video recording
• HDMI out
• Built-in mobile hotspot functionality for up to 8 devices
• Custom web browser with Flash support
• A  kickstand (!)

Below, see the screen comparison between the EVO (center), the Nexus One (Top) and iPhone (Bottom).  Notice that while the phone is about the same size as the other two, the screen extends far closer to the four corners.