L1/i94 expired and F1 is pending. Can i still attend classes

Thank you for your time in reading this.

I am currently on L1B Visa and applying for Change of Status to F1 VISA.

I have already submitted my resignation to my current employer and my last working day is Sept 7th 2012 which same as my i94 and visa expiration date. My classes would commence from Sept 24 2012.

1) For the period of 7th Sept to 24th Sept my F1 application could be in pending status and I will not be on L1B. Can I still attend classes?

2) I have sent my resignation letter to USCIS as well along with i539 just as proof that I am not working after Sept 7th. Will it create a negative impact for my F1 approval?

During change of status you are eligible to stay. But if your COS got denied in later point of time, the extended period of stay is considered to be illegal.