XML is the best way to do it. Simply host your XML into the server and use an LINQ for do that... My server is based in stream, and is a bit more complicated. I'll search for an good LINQ for XML on my database when I back to my home.
if you happen to have a php server just write a php script that outputs md5 or sha1 hash, highest version of the file on the server like a substring of the filename and the php could also write a changelog to the response. thats how i do it on my server