[mikester]

If you're in the US and subject to HIPAA regulations then you would really need to ensure the security of your office computers if they hold patient data.

In that case the easiest solution is a second data line for the purpose of this wireless hotspot for your patients. Not a terribly big deal but still a recurring cost. I would still use encryption however because it isn't a "public" hotspot but one for your customers. Post the encryption details in your office or post a note that says "wireless available upon request." Be sure to provide detailed instructions so that your office staff doesn't become the wireless help desk.

Using WPA-PSK is very easy and just requires a simple pass phrase but provides very good encryption and security. Once you've got your access point setup where you want to provide the Wireless connection to a simple site survey to see how far your wireless signal is readable. IF the signal level is adjustable on your router - adjust it down to where you can only get signal just outside of the area you want so that you are providing good signal within the area you want.

Feel free to question any details here, I've done quite a few wireless implementations as well as secured many a network.