You are correct about Skype's current limitations with WIFI. I too have a droid incredible and wanted to find a solution to make wifi calls when traveling internationally.
TruPhone App worked for me, very easy to setup. WIFI calls from truphone to truephone users are free, and calls to landlines or regular cells are very cheap. I know there is a way to do this all for free but I was not interested in learning VOIP protocols.
Call quality was great with fast internet speeds, but you can hear a slight echo when using the application with internet speeds slower than 1.5 Mbps.