It is recommended that you use a graphics tablet in order to take full advantage of Maya's sculpting features. However, you can still sculpt in Maya using a standard three-button mouse.
You can also operate Maya using gestural input if you have a multi-touch device. See Multi-Touch devices.
If you are using a Wacom tablet, you can find the most current software drivers here: http://www.wacom.com/productsupport/select.cfm.