On t mobiles samsung galaxy s phone can you FaceTime
You cannot use Facetime on your Samsung Galaxy S phone. This is because, Facetime is an application that is specifically designed for Apple iPhones mobile phone. However, you can use Skype or Tango to "Facetime" on your Samsung phone.
If you want to video call from a Galaxy S to an iPhone I suggest you both get Qik. It's a skype based video calling app that works on android and iPhone.