When a small business asks me for my professional advice on setting up WLAN security, I will advise them to use the more secure WPA technology when setting up their wireless network.
WPA offers a highly secure authentication mode and a less expensive but less secure pre-shared key mode. I would make sure they knew to limit access to most network resources.
I would advise larger companies (e.g. government, large corporations) to implement a Virtual Private Network connection to access the specific services and resources needed.