Need small change to Magento site

I have a current, working Magento store. version 1.7.0.0 The programmer that developed it for me has left, and we need a small change made that we cannot figure out in house. On the check out page we need to make it so that "telephone number" is not required. That is it, simple as that. If someone can do this for me quick and cost effective, I will send additional Magento work to them as we need it done.