Texting in Milan
 

My friend and I will be in Milan and would like to text each other if we are separated. Is wi-fi available all over Milan?

If you are absolutely against using the phone network there are certainly wi-fi spots at McDonalds if nowhere else, I bet if you Google Milan Wi-Fi Hotspots you'd find all sorts of them. MilanWifi.com lists them as well so try that.

Have you already come to the conclusion that your current phone does not work off WiFi in Italy? What is your current carrier and what is the model of your phone?

You mentioned TEXT, not INTERNET.
Even if you used a phone as is, if your phone is GSM European band capable, for MMS/SMS text, you are looking something like ~$0.50 per message sent, much cheaper to receive.

Greg is spot on.
Texting has nothing to do with Internet.

Unless you use WhatsApp, in which case you need the wifi or data connection.