My cable modem feeds a router that has 4 ports. One is to a switch, the other to my pc and the last 2 for internet phones.

My wife wishes to get a wireless router for the entire house.

My question is: Is there a way to hook a wireless router to the switch so I can keep my current hardwire network and establish a wireless network so that users in my home can logon anywhere in the house?

maybe you find this information here:

http://www.techspot.com/vb/topic97922.html

just get a wireless Router (Cisco Linksys is my recommendation - probably wireless G - for cost sake - can get for about $40 - 50)
You can keep your exisiting router if you wish (gives you more ports) or just use the ports on the back of a new wireless router. (most have ports too)
I don't recommend hooking up through switch, but rather to have switch run off of wireless router.
you are better to just have one router though with regards to configuration. If you are running the wireless router through another router you have to configure the wireless router to be a 'router' not a 'gateway'. This usually applies, depending on what type of router you get if not a Linksys.