Apple released 3 different sizes models in June 2009

Next Question comes to mind is :

Whats the major difference between these models or what major features are being added to these models ?

Answer : The Major difference between these model is the Physical Size , Display , Battery Life and obviously the Price

The Major Feature Release is the Integrated Battery Life as compared to older Models. These newer one's have integrated Battery hokked up to the circuit board .

13" Model : (Default configuration)

Models : 13" Model Numbers are MB990LL/A ,  MB991LL/A

Max CPU Processor is 2.26 or 2.53 GHZ Intel Core 2 Duo with 3 MB cache

Harddrive : 160 GB or 250 GB

Standard RAM: 2GB or 4 GB

USB : 2

Firewire : 1

Display : 13.3"

Graphics Card : NVIDIA GeForce 9400M with 256 MB of DDR3 SDRAM ( this is shared with Main Memory)

Screen Resolution : 1280*800

Battery Life : 7 Hrs

Weight : 4.5 Lbs

Dimension : 0.95(H) ,12.78(W) , 8.94(D)

15" Model : (Default configuration)

15" Model Numbers are MC118LL/A ,  MB985LL/A and MB986LL/A

Max CPU Processor : 2.53 or 2.66 or 2.8 GHZ Intel Core 2 Duo with 3 MB cache .

                2.8 Ghz processor has 6MB L2 Cache

Harddrive : 250 GB , 320 or 500 GB (depending on the model)

Standard RAM: 4 GB

USB : 2

Firewire : 1

Display : 15.4"

Graphics Card (depending on Model of 15" ) :

        NVIDIA GeForce 9400M with 256 MB of DDR3 SDRAM ( this is shared with Main Memory)

        OR

        

        Dual Graphics Processor -- > NVIDIA GeForce 9600M GT with dedicated GDDR3 SDRAM

                           & Integrated FeForce 9400  

Screen Resolution : 1440 * 900

Battery Life : 7 Hrs

Weight : 5.5 Lbs

Dimension : 0.95(H) ,14.35(W) , 9.82(D)

17" Model : (Default configuration)

17" Model Numbers are MC226LL/A

Max CPU Processor : 2.8 GHz processor has 6MB L2 Cache

Harddrive :  500 GB

Standard RAM: 4 GB

USB : 3

Firewire : 1

Display : 17"

Dual Graphics Processor -- > NVIDIA GeForce 9600M GT with dedicated GDDR3 SDRAM

                           & Integrated FeForce 9400

Screen Resolution : 1920 * 1200

Battery Life : 8 Hrs

Weight : 6.6Lbs

Dimension : 0.98(H) ,15.47(W) , 10.51(D)