Wow...first of all, congratulations, this is a good sign  At least you have the opportunity of getting a job.
What can I tell you about a phone interview...As you might expect, it is a little bit different frojm a normal interview, in the extent that you are not actually facing the interviewer, and he's not able to see you, your gestures, your appearance. But do not consider this an advantage  Body language is quite important. This is why you have to replace it with a perfect verbal and paraverbal language. Verbal, via the words you choose and how you handle the negotiation inside the communication (question-answer, feed-back, straight to the point conversation, no "aaa" no "Ummm"s) and paraverbal via the pitch of your voice. Hit back with confident answers like, "Yes, I understand", Yes, of course" things like that.
Also, take into account that you have to be fully focused on this interview, so eliminate any disturbatory element, like TV, other persons, noise, the dog asking out etc, you understand...
As a suggestion, you might want to exercise your interview. Meaning speak alone in the house, just like that, just to hear yourself and your voice.
Good luck!

Hey congrats! I had a phone interview ten days ago and here is my experience:

It was a long distance call from Middle East to the Southeast Europe and there was very bad connection, I had difficult times understanding the interviewer (british HR manager). Although I was tense, interviewer made it pleasant conversation with lot of questions from both sides and we laughed too on shared experiences from travels. Interview was on the track of CVtips.com guides.

Guess what: I was given an offer (I passed the interview) only through this one phone conversation. Yes this is true, in the morning I have received offer in my email, although I have declined it after short negotiation. That is completely different story.

final advice: be yourself and look forward to it. be positive.

Good Luck!