I would suggest using a calendar like icon with a check in the center to signify today. Then a normal calendar icon to signify other dates. If you search Icon for today, you will see several examples of that icon. Another suggestion would a calendar with an arrow to signify today. This is an example from FontAwesome.
As for your initial question, I would suggest using an "active" styling similar to common practice in HTML. User would be acclimated to this. For instance changing the color of the the current 'item'.