I nearly took down the server twice overnight screwing around with this script of mine - but I'll be damned if I didn't finally figure out the final glitch.
Months ago, I was asked about turning my last.fm Overall Top Artists Cloud WordPress plugin into a Weekly Artists cloud WordPress Plugin. I've accomplished nearly everything that needs to be done and the current iteration is viewable here.
The script requires the PHP 5 function, simplexml_load_file, so if you do not have PHP 5 at your disposal, I am afraid you may be out of luck using it. Before getting too discouraged though, make sure your host has not set things up so that you can use PHP 5 simply by changing the filename extension from php to php5. Some hosts do allow this. A Small Orange Hosting, does, for instance.
It's interesting to note that now that I have mastered how to convert last.fm's XML feeds into a cloud format, I can manipulate all the feeds, since they're all available in XML. Something I might want to mess with later, I imagine.