You should look into caching the results from the XML feeds in a database, as well as caching the output of your app. For example, if your app needs to pull we

You should look into caching the results from the XML feeds in a database, as well as caching the output of your app. For example, if your app needs to pull weather data from one XML feed by city, and stock quotes from another by ticker symbol, consider using a cron to pull these at 5,10,15 minute intervals and store them in a database. Then, have your app always look at the database for the data. You can even cache these queries using memcached, etc. Then, cache the output of your app in a static file and serve that with a 5,10,15 minute timeout. Most of the time your users will get the static cached file, and if not, they will get a page generated from a memcached query result, or pulled from the local database. You never want to serve up that many XML feeds live because when one of them is slow or down, so is your site.