I couldn't come up with a more creative headline for this if I tried. I just found out about this just a few short moments ago, and, I tell you, my head is still spinning.
Disney already owns the video rights to a number of past Marvel cartoon series, including the 1967 Spider-Man series, and the late 90's programs produced by Saban (which Disney bought a few years ago). Now, as the saying goes, they have the whole enchilada. There are those unenlightened souls already making light of the whole situation for their own amusement, of course, but this second Disney-Marvel union (Disney licensed some titles to Marvel several years back) will enable some of Disney's hottest shows (i.e. Hannah Montana) to make the transition to comics, if they choose to go in that direction, bolstering Marvel's presence with "tweens". Of course, there is the inevitable prospect of having ABC and/or ESPN personalities making cameos in Marvel Universe titles.
But what does this do to Marvel's pre-existing movie deals with Fox (X-Men, Fantastic Four, Deadpool), Paramount (Iron Man), & Universal (Incredible Hulk)? Nothing. Marvel will finish out their plans for their movies, starting with "Iron Man II" next year. Beyond that point is open to speculation.
It's just amazing that it took this long. DC has been part of the now-Time-Warner family for more than 30 years, and has prospered. What's next? Fox buying Dark Horse Comics?