Jim, I think this is a reboot for the franchises. Marvel is killing Spidey so I don't know what they have in store, but I listened to a podcast with some artists who work for DC and they said this may be a reboot across the board for all 52 titles. They aren't even sure exactly how it will turn out, but it seems they are starting everything new from the beginning. I'm positive their marketing people came up with this. But if you are out of the loop and want to get in at the beginning of your favorite character's book, now is your chance.
I have only heard this for DC though, not Marvel. My local comic store is having a sale in honor of this. All DC back issues for $1.00.
I also know they will be changing Superman's costume. Mostly the same but losing the red speedo. Here is an article about the costume changes...
Superman's New Costume Sparks Controversy and Confusion/Comicbook.com