It would be great to have an app that would integrate into the OS and allow you to make a google voice call in just 1 click. If you have google voice and have the new Verizon 5 free out of network numbers you can add your google voice and make all calls for free
Please try EasyDialer, it's been used by many Google Voice users. I can not post URL due to 10 messages restriction. You can visit below website, or search EasyDialer on BlackBerry forum.