* Get them signed up on our project management system (ours is a modified version of Redmine).
* Make sure they have a profile pic (it is nice to see their face when they post on stuff).
* Get an instant messaging program or Skype (I use Adium, so it doesn’t matter what platform they prefer.)
* You need some sort of version control. We use SVN for code and Dropbox for non-code (PSDs, DOCs, etc.).
* A conference call system if you have more than two people. We use Skype, iPhone merge calling, and freeconferencecall.com.
* For collaboration, I like join.me and Skype for screen sharing, and Jing or Skitch for annotating and screen casts.
* Get their socials and follow them. The best way to know what’s going on in their lives is through Facebook and Twitter, and since there’s no water cooler in your virtual office, making personal connections online is essential.