How does release of a new model affect the sales and price of the older model?

I know normally the price goes down, but case in point, Nikon D90 has gone up in price in the last month due to lack of availability due to production being slowed and halted to make way for D7000. What are the trends of fluctuation in prices when this has happened before?

Prices of all brands go sky high whether it be a DSLR or point and shoot. I found no free lunch on discontinued models.

If you keep waiting for the next new model or the next supersale, you'll miss a ton of picture-taking opportunities along the way.

As the other said the longer you wait the more you'll miss.

I don't see the D7000 being the D90's replacement maybe the replacement to the D3000 and D5000.

The D90 is both backward and forward compatible, Nikon knows the tech they are working on to come out over the next 10 years, and try to make current releases able to adapt to the future as much as they can. This keep you using their line of products longer.

Price don't go down on SLRs for years… After they are stoped being produced. This is because Camera specialist business will buy up stock of the model and be a limited supplier of them then. Sure you may find one here or there at a big box store for a reduced price but not half price.