where can i find the usb cable for blackberry storm 9530?

You can find the USB cable at a couple different locations!  Amazon is one of the cheapest where it is selling for $3.00
specifics

• The A Days Tech Professional Charging USB Data Cable outperforms the originally manufactured (OEM) cable
• This USB Charging Data Cable provides the ability to connect your phone to your computer with your software (sold seperately).
• Cable also allows access to features such as Phonebook, Internet, Music, Ringtones, MP3, Calendar, etc as long as your phone and software support
• Use your phone as a high speed modem and access Internet to check email, etc. (consult your carrier for this service)
• Advanced charging regulation of this cable is controlled equally by the phone and computer. This means an accurate digitial charge

Another extramly cheap cable is also on Amazon selling for only $.50cents!
specifics:

• Original Blackberry USB Data Cable!
• Transfer music, photos, ringtones, contacts, and more
• No software included

There is also a seller that has the cable as well as a leather holster selling for $5.34
specifics:

• Includes 2 items: Brand New Blackberry OEM RIM Blackberry Micro USB ASY-18683-001 Sync Data Cable and Blackberry Swivel Leather Holster HDW-19819-001 for Storm 9500 Thunder 9530
• Original Data Cable by RIM Blackberry allow you access to your contacts, PC data, the Internet and e-mail. Transfer rate up to 4 Mbps.
• Blackberry Swivel Leather Holster features magnetized proximity sensing technology. Sensor allows you to switch automatically to different notifications settings (for ringing, vibration or both) based on whether your smartphone is in or out of its case.
• Multi rotational RIM swivel belt clip
• (Phone Not Included)