I feel the Bible was very plain in saying that God created the Earth and all the creatures in 7 days. I don't believe this would be divided into days and say what he did each day if it signified something else. It tells us about creatures of the air, of the land, and of the sea. I don't feel there is any need to exclude dinosaurs from that list.
Most of science out there will say that dinosaurs existed millions of years ago, but this is in direct contradiction with what creation will tells us assuming that dinosaurs were made then. A lot of science will tell you that the prints found with human prints in dinosaur prints are some kind of fake or misread and are really something else. I have no doubt in my mind that there are corrupt scientists whom are non-believers that will try to do anything to destroy strong evidence that proves that creationism is the real deal. The Smithsonian has been known to cover up evidence that supports creationism (some may think that this is a big conspiracy).
There has been some found evidence of dinosaur footprints and human footprints together. Dinosaur Valley State Park supposedly has such things to see:
www.genesispark.com
Answers in Genesis looks through these topics, too, and might be worth a look:
An aura of mystery surrounds the dinosaurs. Where did they come from? Did they evolve? Did they really live millions of years ago? What happened to them?
answersingenesis.org
Then there are many theories as to why the dinosaurs died out or mostly died out (if you're like me and still think there are dinosaurs in some parts of the world that exist because they wouldn't have been created millions of years ago). Anyway, most think the flood wiped them out, but if God preserved the creatures by taking two of each kind, there could have been dinosaurs on the ark. There are theories of oxygen levels dropping on the earth before and after the flood, stating there must have been a significant decrease and perhaps this killed off many dinosaurs. Some theorize they were hunted, ran out of food, or there was some imbalanced ecosystem catastrophe. Whatever it was, we may never know for sure.