NO ! NO POLLING !! This is better IMHO ...
Polling is of course an evil thing!
A =MUCH= better idea IMHO, is that when you have a release, you take your description file and email it to the sites. Each announcement site would have an email account that just grok'd the file and updated the database. Then the authors only have to add the sites to an email list/group and send it out to all of em at once. This would stop silly polling while allowing the author to send out changes with a simple file-attach.
Also, to make sure we don't fake emails, I think a GPG/PGP signature would be called for. I know some people are gonna fuss if required, but I really think authenticated/signed email is gonna become a necessity anyway, might as well get used to it.
Those that don't like signatures would probably have to go to the site and manually log-in and then upload the description file, still a bit faster than going all over. It would also be nice if some of the major sites allowed the others to request the description files from their database by date and/or type or allow remote SQL searches.
I do like the idea of a standard format description file, and I do like the idea of adding dependency information up front. In fact, when browsing freshmeat, you should be able to click the dependency so you know where to get it if you don't have it.
Anyone else hate downloading something, finding out you need another file, and then going back on the net to find it. Then you download it compile it, install it, go back to what you were trying the first place, and then find another dependancy you need ... ARGH!