What`s going on: FedEx is switching over to a newer Web Service API, and is discontinuing their older system at the end of May, 2012.
If you`re running Magento Community 1.6 or 1.7.0, you`re fine — this uses the latest system.
If you`re running Magento version 1.5, 1.4 or lower, you need to do a quick extension update, and you`ll be able to continue to use FedEx for shipping quotes.
If you`re not running Magento (but do rely on real-time shipping quotes from FedEx), please check and make sure that your system is going to work after May, 2012.
How can I tell what version of Magento I`m running?
Log in to your Magento admin area. At the bottom of the page (you may need to scroll down), it will read in the center: Magento ver. 188.8.131.52 (or something similar).
How much does it cost to update? The software extension is free; if you would like us to assist you, we can install, test and configure this for you on an hourly basis.