How hard would it be to have wireless access for our customers?

Adding a wireless network is not difficult, but must be done carefully and with security in mind. You do not want customers sitting in the lobby, to have access to anything else on your network. Depending on how much area you need to cover with wireless, it isn't necessarily an expensive project.

Also, you should be aware that wireless is not usually a suitable replacement for a traditional "wired" network. Wireless is not as fast, and all wireless connections must share the available bandwidth with each other. Additionally, wireless connections are subject to interference and range problems.