from my understanding there are no soft phone apps out there or apps like skype and fring that allow you to use the internal speaker. Am I correct? The hope with WM6 is that this issue would be fixed.
The only fix I saw was using Shapeservices' IM+ for Skype, but I can't say it's true VOIP calling. It doesn't use an active data connection for the call. Only use this software with unlimited skype calling. It basically routes the call through ur number and calls you back through your skype number, therefore incurring double the airtime. Once you answer the call it'll also count towards your carrier's minutes.
btw, has anyone seen this article before?
http://nerdvittles.com/index.php?p=124