It's only been a few weeks since we last checked in on the progress orrebmas was making on getting full HDMI mirroring to work on the HTC EVO, and today a public beta of the app that makes it all happen is now available.
Released this morning, FullHDMI enables HDMI mirroring and currently requires that 1) your EVO is rooted, 2) it's running a Sense-based ROM, and 3) you flash this custom kernel (tutorial here). A non-root version was available during private beta testing recently, but it's not working with the public beta. So if you're not rooted, then no, you cannot use this particular version of the app.
Since this is still in beta, there are a few bugs and clipping/flickering issues that need to be sorted out, but it is definitely impressively usable in its current state. The app was designed to keep the EVO as the primary display and mirror its screen to a secondary display via HDMI, so orrebmas says that the FPS on the phone won't be what you see on the TV. He says you can expect "upwards of 40 fps" in 3D games and less in 2D because "the 2D engine does the mirroring."
The purpose of this release, other than to make a ton of people happy, is mass testing and gathering feedback so grab the FullHDMI .apk from the link below to participate in this rather historic event in the EVO's history.[Android Central] Thanks, bradleyw801!