How long before the expiration of EAD and AP can you apply for renewal? I heard you can apply 6 months before the expiration of EAD for renewal. Is this true? Also, is it the same for AP or different? My EAD expires at the end of July and AP expires at the beginning of August.

Thanks.

It's true for the EAD: You can apply up to 6 months prior to the expiration date of your current EAD card.
Also check out this post: http://www.visajourney.com/forums/index.php?showtopic=104474 it's the same question you have.

About AP: USCIS accepts renewal AP applications 120 days before the date your current AP document expires.