Nikon D3100 has already released. Photography enthusiast specially those Nikonians are waiting for the replacement for Nikon D90. D90 was one of the Nikon's best buy because of it's full features.
Rumors have been started that the official name of D90's replacement is D7000. Rumors also says that the features of D7000 is between the D90 and D300s model. And it will be release on the last quarter of 2010.
But let just cross our fingers that the replacement for D90 is still a best buy and will enhance more on the feauture of D90. Let's just wait for it's official release.
According to Nimesh Thakkar of Nikon India mentioned in a Q&A session that there are no plans to replace the D90 and the D700:
Q13: Is there going to be a D700x or D700s? If yes, then when could we expect it? – Dr. Parth
Ans: Dear Dr. Parth, At present, there are no plans to replace Nikon D700.
Q14: When D90 replacement is going to be launched? I’m planning to buy a D90. Is it the correct time to buy it or should I wait? Is there any chance of D90 price drop in another 1 month? – Deb
Ans: Dear Deb, At present, there are no plans to introduce any replacement camera and no price drop can be committed.
My suggestion is that technologies keep changing; you have to decide when to buy. I suggest, do not wait, Nikon D90 is a hot cake, go grab it.
Dual SD memory card slots
16.2MP CMOS sensor (DX)
1080 HD video @24p | 720 @30p (not sure about those)
20 min video recording (up from 5min on the D90)
Save images from video (similar to the D3s)
AF during video
Stereo mic input for video
Virtual horizon (like the D300s)
One touch video and/or live view (similar to the D3100)
Improved ISO range: 100-25600
39 AF points
Weather proof (like the D300s)
New battery system
Expected price: $1199 for body only
Update: no swivel display
Just to let you know. The picture of D7000 is just an edited D700.