I use both, Phoner and PhonerLite VoIP-softphones inside my PortableApps on my USB-drive. Both work perfectly well. So I'd like to suggest to add them both to your list of apps. There is already a .paf.exe file provided by http://www.phonerlite.de/download_en.htm for PhonerLite. For Phoner I just unzipped the phoner.zip file from http://www.phoner.de/download_en.htm into my PortableApps folder and renamed it to PhonerPortable.