Mmmm...maybe. Probably...idk. Some have special egg groups its kind of complicated :P http://www.serebii.net/pokedex-bw/egg/bug.shtml check out this site, it has lists of the egg groups and stuff. Helps ALOT trust me, but there are some egg groups that cant breed and etc ya know? Im not sure about all of it.
Usually as long is ones a male and ones female it will hatch an egg. No legendaries can be bred, and also the daycare raises the levels for you (but it will erase moves if it learns new ones while it is in there) Most people use a ditto and another pokemon of any gender as long as you arent breeding for special moves and such.