USTA Find a Partner Program
Here’s a handy site that lets you put in your profile and find other players either in your area or when you are traveling who want to hit.
In your profile you can tell exactly what you like to do. If you’re just a social player that wants to hit the ball around a little bit, then check that box. If you want to play full out matches with scoring, then check that box. If you want to do practice drills, then check that box.
Check it out at http://findapartner.usta.com/