How do I report a bug in Safari 6.0?
http://bugreport.apple.com is the canonical bug reporting mechanism. Once you have submitted an issue, it will be given a "radar" number and you will be treated to possibly the most archaic customer-facing bug reporting interfaces on the planet.

You will want to first select a developer account and agree to Apple's terms. In your case, the free of cost Safari developer program might be very useful if you care to know what changes are in store for Safari.

https://developer.apple.com/devcenter/safari/index.action