Quick xml updater

I’ve got a blog on my site, using an xml file to get the posts.

My question is, where would I start to make a little flash site that would let me update the xml file without re-uploading a new version to the server. I assume I would need to use PHP and AS . I’d take variables from textboxes (Title and body) also, it would need to get the date automatically. Then, I would have to use PHP or something to put those variables into my xml file with the correect tags and save it.

I’m not sure if this is really complex or quite easy. I don’t know where to start.

Any help or suggestions are welcome.

Thanks!