I have few queries regarding GMAT ?

Hi, this is Anand; I am writing to you to inquire about GMAT. I completed Engineering this year (June2008). I’ll be joining a software company soon. As GMAT score is valid for 5 years so um planning to appear for GMAT in Nov.2008. I’ll be applying for MBA in JAN2011 (by the time I’ll have abt 2 yr work exp.). I have few queries regarding GMAT. I would be thankful to you if you could please answer them.

1. As I’ll be appearing for GMAT in Nov.2008 and I’ll apply for MBA institutes in JAN2011. I’ve heard that many universities do not accept GMAT score which is more than 2 years old. Is it true?

2. Is it necessary to join any coaching institute for GMAT preparation?

3. How many months preparation is required and which books are best for GMAT preparation?

I am looking forward to hear from you.
Thanks
Anand