My H4 petition for change of status from H-1B is about to be filed. I am wondering when should be my last working day with my employer. Can I leave the job as soon as my H4 petition is filed? Or do I have to wait until I receive the notice of receipt from USCIS? Please advice.

You should remain on H-1B until H-4 is approved.

Think about unexpected situation that might happen to you.. it already happened to thousands of people. The petition was denied because the consulate is convinced that this is marriage for convenience... or the marriage was accepted by religion but not by the law... or insufficient proof of relationship, or etc. All attorneys know what might happen but very few will tell you that you may be 1 in 1000... when one gets paid for consultation, why not hold a little bit so that the client will definitely come back when thing did not go well as expected. There are 2 sides on every coins... Be wise.

tallapa, we are in a similar situation.. what is the resolution to this issue? I am planning on applying for my wife's H1-H4 COS. Can she quit her job when the H4 COS is pending?