I teach DTU TOEFL Preparation in my office (Pusdiklat Keuangan Umum BPPK), and my specialty is listening. Since 2007, we have been teaching iBT TOEFL for the government officials of the Ministry of Finance (we used CBT format from 2003-2006). Here I will share you some strategies to improve listening skills, especially for the iBT format.
The best way to improve your listening skills is to listen frequently to many different types of material in various subject areas (sciences, social sciences, arts, business, etc). Watching movies and TV and listening to radio is also an excellent way to practice listening. Audio tapes and CDs of talks are available in libraries and bookstores; those with transcripts of the listening material are particularly helpful. The Internet is also a great resource for listening material.
Improving listening skills needs a lot of practice. Here are some websites that you can visit for listening sources:
http://www.bbc.co.uk/world service/learning english
There are still hundreds more. So, find them yourself and …happy surfing!