Here are two versions:
[code:f4b2d]<object classid="clsid 27CDB6E-AE6D-11cf-96B8-444553540000" width="400"height="80"><param name="movie"value="http://www.2and2.net/Priv/yoursig1.swf"> <param name=quality value=high><embed src="http://www.2and2.net/Priv/yoursig1.swf" quality=high type="# width="400"height="80"></embed></object>[/code:f4b2d]
[code:f4b2d]<OBJECT classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" WIDTH="400" HEIGHT="80" id="sig">
<PARAM NAME=movie VALUE="http://www.2and2.net/Priv/yoursig1.swf"><PARAM NAME=quality VALUE=low><PARAM NAME=bgcolor VALUE=#FFFFFF><EMBED src="http://www.2and2.net/Priv/yoursig1.swf" quality=low bgcolor=#FFFFFF WIDTH="400" HEIGHT="80" NAME="sig" TYPE="application/x-shockwave-flash"></EMBED>
</OBJECT>[/code:f4b2d]
If I'm not mistaken PhotoBucket will allow you to upload a swf file now, but if it is a large movie you may have issues finding a free uploader, however this is an option:
http://www.2and2.net