I just bought a blackberry cell phone on EBay

It might be for Verizon if there is no sim card slot otherwise on blackberrys the sim will go behind the battery

The best way to unlock your Blackberry is to buy unlock codes from a trusted vendor. Search internet for mobile phone unlocking websites. You will come across a thousand websites who can do this. Choose which ever you like. Do look for price comparisons and the unlocking instructions. Recheck the Model number- Network to which your phone is locked to and the IMEI number before placing an order. If you made any mistakes in these details these people will never give you a refund!! One more thing, before placing an order ask them about the conditions for getting a full refund in the case of a code failure! Think and make a wise decision. I have personally bought the code for my Blackberry Storm from unlockgenie.com. It is because they have good reviews on most of the mobile phone forums. I got my phone unlocked successfully from that website. I think their codes don't fail. The web link for the above mentioned web site is http://unlockgenie.com/

You have to contact with your internet service provider.

you can normally download the cd from the internet. find a friend with the cd or go back to the shop you bought it from

You can dowload some of the drivers and desktop software for free from the manufacturer - here

http://uk.blackberry.com/services/

Here is the link for the USB Drivers:
http://www.motorola.com/consumers/v/index.jsp?vgnextoid=bda09ec8009a0210VgnVCM1000008806b00aRCRD

Here is the link for the Motorola Phone Tools Utility: (Vista 32 and 64 bit)
http://lfiles3.brothersoft.com/internet/mobile/Motorola_mobile_phone_tools4.5.1.zip

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http://na.blackberry.com/eng/support/devices/devices.jsp#tab_ddetail_subtab_8700

here u can find ...

Hi,
http://na.blackberry.com/eng/support/devices/devices.jsp#tab_ddetail_subtab_8700

Here is what you need!!! Click on the Above Link. Download Software and manual!!! 
Hope This Helps!!!  Please Rate my Response!!! Thanks!!!
PREM

Hi,

You can download here from Blackberry.

http://na.blackberry.com/eng/support/docs/subcategories/?userType=1&category=BlackBerry+Smartphones&subCategory=8700+Series

You would have been given with the driver CD, but it is to be noted that and made sure weather that driver or installation software supports Vista.

Thanks