Yes, Integral USB 3.0 Flash Drives and card readers are backwards compatible with USB 2.0 and USB 1.1 ports. The USB 3.0 Flash Drive or card reader will work at the speed of the port, for example if you use a USB 3.0 Flash Drive in your USB 2.0 laptop, it will work at USB 2.0 speed.
To use USB 3.0 ports you will need a driver from the manufacturer of your PC, motherboard or PCI card. The standard USB Mass Storage Driver from Microsoft (included in Windows XP/Vista and 7 will work - but may not provide optimal performance. Microsoft Windows 8 fully supports USB 3.0 SuperSpeed devices and includes all required drivers for desktop and laptop PCs that feature USB 3.0 ports.