Thanks for the note, however I found this quite strange. Especially, that the WGA had nothing on their website.
So....I called the WGA at (800)548-4532 and probed my way to their "Contracts" department. "BINGO"
I was FAX'd a Writer Collaboration Agreement. Tried to get a Word .doc copy but no dice, so a lot of UNNECESSARY retyping to do to use as a template for various co-writing ventures.
Actually, I see the need to further modify it to cover some issues.
I wasn't satisfied with the response as to why the Sample Agreement wasn't up on the WGA website, so was transferred to their web guy's extension and left a message "encouraging" the powers-at-be or whomever to get it up on the web.
Hope this info about the availability of a WCA helps someone else.