Before I go into any details, I would just like to say that yes, I know there have been several other posts about this particular program. But I am posting again because I would like to point out that Songbird is still in development and it is unlikely that a portable version can be made if there is no official release of the application yet. So for anyone who would like to request Songbird as a PortableApp, be patient and wait for them to work out the bugs.
FYI: Songbird works fine when installed on a portable device. I have it installed on my external hard drive and it runs perfectly. My music is also located on the external hard drive.