Is LCA (Labor Condition Application) a must for H-1B filing?

Can the employer apply at any time but before H-1B?

yes, it's a must for the H1-B filing and needs to be done before they can file for H1-B. The following website has really good information about the process.

http://www.foreignlaborcert.doleta.gov/h-1b.cfm

Thanks MR Nice Guy

could u tell me what we should write on the place of start and end date of employment while filling out LCA. I was asked by somebody. So I want to make sure.

Is it H1B start date or actual start date (on OPT)? 

you H1-B will not kick in untill october 1st (unless you are reinstating your H1B) so i would put the starting date as oct 1 and end date three years from that date.....since, H1B are for 3 years only....

This is what I think but don't sue me if I am wrong.