iTunes and Amazon.com lead the pack with a 720p version is available for $14.99 and $16.99 respectively. Amazon has encode the film at a slightly higher 5000 kbps bitrate (4 GB total), while the Apple edition clocks in at 4043 kbps (2.9 GB). Vudu also offers a 1080p version for $13.99, although it appears that this edition can only be streamed, so the compression may be somewhat more of a factor. Via each service's respective partnerships, owners of the movie can then view on their computers, televisions and mobile devices via the associated app for the XBox 360, Playstation 3, tablets and so on. Note that an HDCP-compliant (such as HDMI) connection is required for viewing the HD edition on a computer/certain devices, and the specific hardware that each service supports varies, so be sure to double-check what you're getting.
The new iPhone 5's 1136x640 resolution screen is an almost-perfect fit for the 1280x546 video from iTunes! Here's a handful of screenshots of the movie upscaled to the iPad 3's native 2048x1536 resolution.
We're still anxiously awaiting a Blu-ray release, but until then, it's wonderful to have an HD Wing Commander in both my pocket and on my big screen!