Dear Mehran,
You mentioned the Nosrat CDs. I have tried them. They are not so useful, but they got a great advantage. All words and sentences are said by native speakers in these cds in American accent. You can be sure that they don't mispronounce any word.
I've got a piece of advice for you. Try your best to learn English with the correct accent. Almost all Iranians who learn English inside Iran make so many mistakes in pronouncing words. They have a sort of accent that can't be called anything but Iranian English!
.gif)
Your friends may find it funny that you talk in the coorect way, but it doesn't matter. The day in which they talk to a native speaker, they will be the ones who are laughed at!
.gif)
As you know, there are two major English accents ,British and American. What you hear in most of movies is the American accent. I, personally like it more, but it all depends to your taste.
G
ood Luck!