Ok first thing, what is your URL?
Next, if this is hosted on your own server, consider turning up the ammount of memory available to your wordpress instance in your php.ini (for linux this is under /etc/php.ini remember to recycle apache afterwards) I usually set mine to give PHP 128Mb for a production site. Remember memory is cheap, your time isn't!
Also if your doing your own hosting make sure you've installed APC cache. It really improves PHP all around performance. If your slowness us being caused by really high traffic. Then it's time to consider load balancing your site or at the very least using a CDN (Content Delivery Network) to serve your files.
If you are not the one hosting the site, then perhaps it's time to consider switching hosting providers. I think in this crowd you'll find Dreamhost is among the favorite, and not just because they support WordCamps!