Yep differs by school, so your best shot will be to contact the schools you're interested in and ask about your particular situation. For some schools it doesn't even matter where you live or where you go to school as long as you're under 24, because it'll be your parent's residency that matters.
Also keep in mind that state residency (like for taxes and car registration and stuff) aren't always the same as state residency for TUITION PURPOSES. so don't go around just googling 'Alabama state residency' or something