It is said that within two weeks time Apple will unveil a iPod mini with a bigger HDD and color screen. The color screen of the new mini will be a full-color TFT screen with a resolution of 176*132.
The form factor of the player will stay largely the same as its predecessors. Its not sure how big the HDD will be, some sources hint it might be a 6GB model but currently Seagate's biggest model is only a 5GB HDD.
The price of the iPod mini will remain the same: $249.