While doing directory submission we many times cross across sites with same ip. where we submit our site. And there are many sub domain directories too. Would plz give us light about this kind of directory submission. Is this kind of submission help? or should we have submit in sites with different IP.

There is no benefits in submitting websites to directories with Same IP address. Even if you found websites with different IP address, you would not get any benefits unless the page at which your website link is displayed get indexed.