Q: Where can I download BootCamp 3.0?

If your OS X 10.5 or 10.6 DVDs are not readable, is that true in Mac side also ?

Internal or external?

Apple use to provide direct downloads of the updates - 3.1 thru 3.3 but really TELL US what Mac OS you use, maybe if you try from inside Boot Camp Assistant you can.

I would not be using Boot Camp 3.x with Windows 7 if I could use BC 4 or 5.

http://support.apple.com/kb/HT5639

Mac 101: Using Windows on your Mac via Boot Camp

https://support.apple.com/kb/HT1461

Helpful Apple Support Resources (Forum Overview)

• Boot Camp Support 
• Boot Camp Manuals

Boot Camp 5.0 Drivers

http://support.apple.com/kb/DL1638

Boot Camp 4.0, OS X Lion: Frequently asked question

http://support.apple.com/kb/HT4818

http://manuals.info.apple.com/en_US/boot_camp_install-setup_10.7.pdf

The Boot Camp Assistant can burn Boot Camp software (drivers) to a DVD or copy it to a USB storage device, such as a flash drive or hard drive. These are the only media you can use to install Boot Camp software.

https://support.apple.com/kb/HT4569

• Installation Guide

  Instructions for all features and settings.

• Boot Camp 4.0 FAQ Get answers to commonly asked Boot Camp questions.

• Windows 7 FAQ Answers to commonly asked Windows 7 questions.

http://www.apple.com/support/bootcamp/