I am a us citizen filing i130 and i 485 for my biological under 18 year old children .Do I need to also file i 864?and g 325?

yes

If you have a removal order how many years does it last for?

10 years from the time he left the U.S. If he has not left the US and only found out recently about the order, he may be able to request...

I had an H1b visa approved and stamped in 2007. Will I be exempt from the H1B cap of 65000?

No

Can I change employment with a non e-verify employer who willing to file H1-B, while on stem opt extension?

The employer does not have to be e-verified to petition you for H-1B status.

You must consult with an immigration attorney as to the charges and time of the conviction in order to determine whether they can lead to removal...

HOW LONG IT TAKES FOR A HUSBAND OF A PERMANENT RESIDENT TO GET HIS GREEN CARD?

The priority will become current in about 2.5 years from filing of I-130 depending on country of origin.

Do I qualify for the new I-601 waiver ??

Yes

PostL1B expiry, what is theLegal status of I94 issued at port of entry if no explicit visa extension done to obtain extended I94

The date on your I-94 determines the validity of your status as long as you work for the company that petitioned you.

My L1B Visa with Company A is expiring AUG-2013. Company B is filing H1B (COS) but company A is sending me back to India in AUG.

You can return with a valid visa if you will work for the company that petitioned you.

To apply for visitor visa .. Do I need to disclose that my sister is in u.s.a.? Even if we don't have relations..

Yes, you must disclose any relatives in the US on the visa application.