If i install Linux in windows xp com can i access xp? (If it is in different drive)?

Answer 1

Yes, that is called dual booting this explains how to do it.

Answer 2

you actualy can have xp running in linux (or linux running in xp) without installing a new operating system on your machine.

if your machine is not too old, you probably can get the best of both worlds.

try vmware server or Virtual PC 2007.
both free.

but back to your question, yes linux can acess NTFS file systems, at least read them. (you might have problems writing to them due to patent reasons)