You can do a Google search and gets tons of info. Let me give some of my experience. I know cross drilled rotors look cool. I plan to run them on my 82 Blazer, but they are not vey practical. They do tend to stress crack, but this can be prevented if you have them cryogenic treated before you run them.
They "can" be resurfaced (turned) if you have a brake lathe with the proper cutting bit. The common style of cutting bit is pointed and tends to chatter. If you use a cutting bit that is "bull nose" or rounded and go slow it will turn them just fine.
Another big controversial issue about cross drilled rotors is the amount of swept surface you loose. In high performance or racing applications the benefits of the cooling effect outweighs the surface lost from drilling. In most applications the rotors are larger than stock as well, so you actually have more surface area.
In average driving use or applications where the rotor size has not been increased cross drilling becomes a trade off. You have the cool look but you do loose some braking performance by having less surface area.
If you want the best of both worlds consider using slotted rotors instead of cross drilled. Since slotted rotors have machined slots in them that do not go completely through, they "almost never" suffer from stress cracking. If they are cryogenic treated they are very durable.
Slotted rotors also offer the advantage of running cooler as well as pulling trapped gases away from the pad that causes them to float on the rotor. They can be turned on a lathe with a conventonial bit as well. You do have to make smaller cuts until you get a smooth surface.
Just my .02 based on my experience...let the flaming begin...
