Alternatively, look for an Intel Centrino sticker somewhere on the case. It it has the sticker, the laptop is wireless enabled.
Intel Centrino Mobile Technology is a marketing name for a combination of the Intel Pentium M processor and Intel's' Pro Wireless card.
If you can't find a sticker the next step is to right click on your "My Computer" icon and select Properties. When the menu opens look at what it says after or under the word Computer.