I'd like to post this where I know there will be the most advanced users reading but this will have to suffice. :) No offense to anyone, I just know this is rather advanced.
Without using a cron job (remember, this would have to work on a Win32 box as well), would there be anyway, using XMLRPC or other trick, to determine if an RSS feed has been updated.
The theory is is to write a plugin that will essentially merge entries from a friend's RSS feed into my own blog. That's the easy part. Figuring out when to query an updated feed is another.