eBoostr™ allows you to use an additional drive (flash memory or hard disk) as another layer of performance-boosting cache for your Windows XP®. There is no need to purchase a Vista upgrade to get the benefits of the Vista’s ReadyBoost® technology. With the newly developed eBoostr™, the booting of your OS and applications startup get much faster thanks to the smart caching mechanism.
-Vista’s ReadyBoost benefits on your Windows XP® machine;
-Smart caches frequently used applications and files for maximum performance speed up;
-Supports both USB and non-USB removable media devices, as well as additional hard disks;
-Allows up to 4 devices for simultaneous smart caching;
-Cache file size of up to 4GB on each device;
-Compatible with all ReadyBoost® ready devices.
Here's the official website: http://www.eboostr.com/