The new CPUs are just Intel trying to fill out the lower range of their line. Really, they seem really over-priced to me for what they are- when you have the i5-750 true quad core for the same price as some of their new dual cores with a "graphics core" built in, why would you EVER buy the dual core? I mean, if you are spending $150 or more on a CPU, then you are probably already planning on buying a dedicated graphics card anyway right? And with AMD's true quad core Athlon II x4 at $100, why buy a dual core i3 for $115-120? Oh well- just my take on them.
They are different chips, yes. They aren't aimed at the same market though. The i7-950 is faster than any of the new stuff that came out, but also more power hungry and hotter. If you have an i7, I wouldn't worry about upgrading for quite a while.