The method that is recommended for ALL objects, is the longdesc attribute in your OBJECT tag. The longdesc value is specified as a URL, such as an HTML page, but it could just as easily be a TXT file, assuming most user agents can access it.
Some sites have a single 'glossary' type of LONGDESC file that contains a continuous list of descriptions, each with a fragment identifier.
HTML Code:
<h1>Transcription of SWF files that appear on this site</h1>
<dl>
<dt id="jellydonut">Transcription of Jelly Donut SWF video</dt>
<dd>How do we get the jelly to stay in the hole? Lorem ipsum, ...</dd>
</dl>
Alternatively, if only one object appears in any one page, then the transcript could be in a fragment on the same page. In either case, the URL in the longdesc value is not well supported, so a link to the transcript should also be included in a conspicuous location near the object.
I'm not sure if the URL in the longdesc value can contain a fragment hash, so I would recommend examining this further.