Because recruiting is a process that takes a long time to inform oneself and execute properly, it should be noted that the process should not be done overnight; give yourself at least two weeks to prepare everything stated below.
The phone interview is given to candidates who have passed the first round of screening at a job fair. From your resume, they see that you are a potential intern/employee, but they need more information about who you are, how you handle pressure and conflict, and what you want from the company.
Overview
To have a successful interview, it is always best to 1) be calm and 2) know your resume inside and out. It's as simple as that.
The Q/A
Although the process is simple, there are a lot of ways to strategize the process of your answers by not having to think on the spot more frequently than you have to. Come up with your examples of teamwork, leadership, and other difficult obstacles that you have had to overcome to be where you are today. If you do this, you will have ammo for any behavioral question that the recruiter will throw at you.
Other Tips
Be genuine: You can spot a person that just spouts things you want to hear a mile away. Be honest and thoughtful with your responses, and you will be able to go a long way.
Smile: When you smile, you will sound happy. If you don't, you might sound unenthusiastic, or off putting. This is a huge part of how you come off as on the phone (try it in regular phone conversations).
Be patient: If you scheduled a phone interview at 12 and the interviewer hasn't called you for 10 minutes, do not call him/her. They are probably on another call with a prospective intern.
Have notes: Have notes in front of your when you go into a phone interview. However, do not speak verbatum; it will reflect as droning and it may be obvious that you are reading responses of a page.
Conclusion
The phone interview can be hard if you are not prepared, but with these tools and tips, you should be able to have a successful interview.
All of the information that you will need is in the "Interview Guide" file provided above.
Again, be relaxed and confident after preparation; if you have gotten an offer to come to an in-house interview, it means that you are qualified, but the recruiter wants to see how you act in person.
You will usually be assigned a associate to guide you from room to room. Be friendly to him or her, because he or she is part of the recruiting process.
You will be interviewed (usually) by two managers/directors and a partner. You will be asked 3 - 5 behavioral questions and then will be given about 30 - 40 minutes to ask your own questions. This is an opportunity to ask them anything you want, so make sure you come up with questions before hand to ask them (again, examples are in the file above). If you would like to, you can even ask manager or partner specific questions.
After your interview, the firm will most likely take you to lunch. This is not the time to check your phone, talk with your mouth full, or act completely relaxed. This is still a professional setting, and a secondary test to see how you are outside of a work setting (especially in a restaurant setting).
Finally, thank everyone that interviews you, and talked to you during the interview. A thank you goes a long way (again, look at the file above).
Congratulations, you got the offer to intern at an accounting firm!
Although this is a huge step in your career as a future CPA, there is still a long way to go. During your internship, you should utilize the resources given to you, and should establish that you are a capable team player.