Do please check out Lori's link above - sounds like you;re starting from scratch and that's a good place to start.
In the meantime, quick answers:
what should the temp's be in the cage, basking spot temp, etc.
Around 21 degrees C at the cool end and 31 degrees C at the warm end (70-88 degrees F). Corns are not a basking species and do not need a basking spot.
No. In the wild they are mainly active at times of low/no sunlight (dawn/dusk/night) and have never evolved the dependency on UV light that some other reptiles have.
Do they prefer infared light over bright lights?
I've never used any sort of lights, so can't answer this one. Hopefully someone else will be along soon who has experience of this aspect.
How often do you feed a corn a mouse?
Depends how old the snake is. Hatchlings eat one pinky (baby mouse) every 4-5 days, while and adult Corn will eat one adult mouse every 10-14 days. Use this board's Search facility for "Munson Plan", which is an excellent set of guidelines on feeding and when to move up to the next size mouse.
Can they eat anything else besides mice and/or rats?
The fat content of rats is higher than mice, so most folks stick to mice. Corns can eat chicks, although these act like Snake Drano and produce the smelliest poop ever. They can also eat things like hamsters and anoles, although these are very expensive habits to get into. Corns don't get "bored", so there's no need to feed anything other than mice.
What is the perfect sized enclosure for a full-grown adult cornsnake?
As big as you can get! The minimum size I use is about three feet long x one and a half feet deep x one and a half feet tall. But I have others that are three feet tall and three or four feet long, with climbing shelves and different levels.