The RIM BlackBerry Curve 8520 is available exclusively through T-Mobile.
T-Mobile is still catching up in the BlackBerry game, but is getting closer to the competition with phones like the BlackBerry Curve 8520. Just as T-Mobile is new to the BlackBerry game, the Curve 8520 is for those just getting into the smartphone game; that is, if you’ve never owned a smartphone before then this is the one to go for.
Trackpad instead of trackball

The trackball is an infamous sign of BlackBerrys. The Curve 8520, however, is equipped with a trackpad, which may turn some people off. It’s the same concept but a little foreign, and everyone knows people hate change once they’re comfortable. If this is your first BlackBerry though, then you should be in good shape! It’s not hard to get a hang of, and it’s definitely pretty convenient.
BlackBerry Internet Service
You can set up 10 personal/business POP3 or IMAP4 email addresses through BlackBerry Internet Service. Along with this, the BlackBerry Curve 8520 got an attachment viewer that will open tons of file types, not limited to but including Word, WordPerfect, Excel, and JPEG. This is because of the Documents to Go application that is installed, but if you want to create new word documents you’ll have to upgrade to a premium account.

Apps? Some, but not a ton
BlackBerrys have an App Store similar to the ever popular Apple iPhone’s. The Curve 8520, however, isn’t on quite the same stage as the other BlackBerrys. You see, you can only save your downloaded apps to the internal memory and not to an additional microSD card. This wouldn’t be an issue if the Curve 8520 had more internal memory, but at only 256 MB you can only save a few apps at a time.
As there’s not much internal memory, you’ll want to use a microSD card in order to save all your multimedia files. You have all types of music and video files that are playable on the Curve 8520, and can take plenty of pictures with the 2.0 megapixel camera.

Battery Life
You’ll get about five hours of talk time which is pretty decent for a BlackBerry. You’ll drain the life the most by downloading the apps, so make sure you try to only do so when you’re connected to WiFi and plugged into your charger.

Phone Specs:
Manufacturer: Research In Motion Ltd.
Part Number:CURVE8520BLKTMB
Telecom
Data services MMS , SMS , E-Mail
Cellular enhancement protocol GPRS support
General
Dimensions (W x D x H) 2.4 in x 0.6 in x 4.3 in
Weight 3.7 oz
Built-in devices Camera , Digital player
Color Black
Memory
Installed ROM 256 MB Flash
Flash memory installed 256 MB
Input Device
Input device type Keyboard,  Trackpad
Messaging / Data Services
Internet Browser Yes
GPRS (General Packet Radio Service) Yes
Mobile Email Yes
Messaging Services RIM BlackBerry VM Client
Cellular
Cellular technology GSM
Service Provider T-Mobile
Band / mode GSM 850/900/1800/1900 (Quadband)
Phone style Candy bar
Vibrating Alert Yes
Call Timer Yes
Wireless Interface IEEE 802.11b , IEEE 802.11g , Bluetooth 2.0 EDR
Conference Call Capability Yes
Phone Navigation Buttons Trackball
Voice Recorder Yes
Polyphonic Ringer Yes
Digital Player / Recorder
Digital player supported digital audio standards AAC , AMR , MP3 , WMA , AAC + , eAAC+ , WMAPro
Display
Display type 2.6 in TFT active matrix
Color support 65K colors
Max resolution 320 x 240
Power
Battery installed (max) Lithium ion
Max supported batteries 1
Talk time 270 min
Standby time Up to 408 h