Question:
Do I need to submit the I-485 form at the same time as I-140 form?
Answer:
USCIS does not require one to submit I-485 at the same time. Petitioners submit it for number of reasons such as to get an EAD or Advanced parole. EAD and AP petitions can only be applied along with or after 485 petitions.
Q1:
Also, I am under OPT (optional practical training). I have my employment authorization until November 2011. Do I need to send this again?
Answer:
The new employment authorization from I-485 petition will be associated with the a different/new status (called pending 485) rather than like your current F1 status. If you want to work after November 2011 your current OPT cannot be extended beyond that date then an EAD obtained using 485 petition will be helpful.
There is one risk in applying for I-485 with F1. I-140 petition implies intent to immigrate. Therefore, if the I-140 is rejected then you cannot obtain further extensions to your non-immigrant F1 status or OPT. In this situation, any new job should be based on a different (from OPT EAD) work visa such as H1B. Generally this may or may not be a concern to you but you should be aware of this situation also.