i am on L1-B visa with company X visa valid till March 2011.My wife is also on L1-B visa with same Company X,visa valid till March 2011.
1)What time should i resign from CompanY X?
a) When I submit application for change of status I 539 (Application To Extend/Change Nonimmigrant Status L1-B to L2).
b) Once i get the approval for change of status.

2) If I choose option (b) i.e. resign after i got the approval for L2/EAD,i have to serve 1 month notice to Company X.will it be legal for me to continue working for Company X for notice period of 1 month as my status would have changed from L1 to L2?

3)If I choose option(a) i.e. resign after i have submitted paper for L2/EAD and before approval ,can i continue to stay in US if i don't receive approval after my last day in Company X?