More info...
Brad - Thanks.

And you're right... I didn't try to answer dobro's notation question. That last *ahem* "little" post took about 2 - 2.5 hours to complete, partially because I lost my login to the bbs when I was ready to post.

However, I find that a good summary helps a great deal when looking up information, so it was time well-spent.
Now, I don't work in copyright research for a living, and I may be missing something, but as best I can tell...
dobro - This information is taken from the two tables I mentioned in my other post (see above). The crucial part of the form is the "Nature of Authorship" section (Space 2 on both Form PA and Form SR). According to
circular 56a, you must enter "Music and Sound Recording"
or "Music, Words, and Sound Recording" in Space 2 of Form SR to claim copyright for both songs and album.
A more detailed table in
circular 56 gives detailed scenarios, along with which form to use, and what to put in Space 2, "Nature of Authorship". According to this circular, if the you create the music and perform it, recording the performance, and can claim copyright in both the music and the recording, you would enter "Music and Sound Recording"
or "Music, Words, and Sound Recording" in Space 2 of Form SR (same as above).
However, if you can only claim copyright in a song, not the performance, you would submit Form PA with "Music and Words" or "Music" in Space 2, and the performer, who can only claim copyright to the recorded performance, would enter "Sound Recording" in Space 2 of Form SR.
Ideally, if you wanted to claim all rights to everything on the album, you would have had to have each performer/group of performers sign a agreement before recording that indicated the work they did on the album was "for hire", or at least that you will hold the copyright to any of the performances that you record for the album.
If your album is already completed, you might be able to have each performer/group of performers sign an agreement that surrenders their copyrights to their recorded performances to you.
The agreement would essentially be a piece of paper that gives you documented proof of a performer or performers allowing you to claim copyright in their recording(s). As far as written vs. verbal agreements, it may seem awkward to ask for signatures of friends on a recording, but I read a while back (while researching copyrights for something else) that even the most trusting and friendly of verbal arrangements can get ugly when something becomes lucrative. In other words, if you get it on paper, you avoid potential conflict later on.
If you can't obtain permission to claim copyright on all material in the album, then it gets a little tricky. I'm not exactly sure how you would handle it, but it seems that you would have to break up the album, having all copyright claimants register the copyrights for their work.
For example, you write all 4 songs on a demo, and record songs 1,2 and 4 entirely by yourself. However, on song 3, a friend plays a guitar part he/she wrote (you play everything else). Unless your friend surrenders his/her copyrights to you, you could claim copyright for both the musical composition and sound recording of 1, 2 and 4 on a single Form SR, but you would have to file a separate Form SR claiming joint ownership of the copyrights for song 3. If you wrote the guitar part your friend played, you would have to file a Form PA to copyright the musical composition, and a Form SR claiming joint copyright of the sound recording. (now you can see why the previously mentioned agreements are a good idea)
All of this may seem like a hassle, but the basic point to keep in mind is that you are not
creating a copyright - the material is copyrighted the minute it is put into tangible form. You are merely claiming documented proof of a copyright, whether for musical compositions (songs) or sound recordings (in this case, albums).
Brad - Feel free to elaborate on anything I may have overlooked, or correct any mistakes I have made (hopefully none...

).
Hope this helps.
