-Yes.
How can I do that? some of my friends told me it does not matter, just send the application. However, what I read from the instruction of the I-130 and I485 is that it is illegible to send the application if you are not legally stay in US.
-Not true for the US citizen's parents, spouse and kids. As long as you parents entered U.S. with a valid visa (e.g. B2), you can file I-130 and I-485 concurrently no matter whether they are out of status or not.