After wasting almost an entire afternoon researching this app, I want to spread the joy and make sure you guys don't waste your time as well. I will give you all the highlights here:
This particular Wi-Fi calling app is an app that comes pre-loaded on the EVO 3D's from Rogers. This app can enable unlimited Wi-Fi calling and it does not use up any of your minutes. So, in theory, this sounds like a fantastic app. But, the trick to this app is that you need to pay for this service to access it. So if you are looking for a free app, this is not it.
In the case that you have this service on your plan and need to re-establish it (e.g. you flashed a new rom and need to get it up and working again), there is an excellent guide on how to do that on xda from the user "m1613" (the particular guide is for sensation but it also works on EVO 3D, I tried it myself and it worked out great)
Hope this helps other Rogers users out there