H1B transfer questions? help please!

i read some articles in this web. it is better to change employer after work 3 month of h1b from initial employer.

my situation is. i have used 3 years h1b with initial employer. and right now IE(initial employer) is doing extension petition for me. filing and receive receipt in July (extension period 07/2006~07/2009).

now i want to change company, do i need to work 3 month for IE? This 3 month starting from 07/2006 OR 10/2006(FROM h1b extension processing date for approval)?

any information is appreciated!