Open website, page jumps top to bottom back to top.

Mac OS X (10.6.6) < your profile

Try updating your system software to v10.6.8

Click your Apple menu top left in your screen then from the drop down menu click Software Update...

If your software is already up to date, go to ~/Library/Caches/com.apple.Safari

Move the Cache.db file from the com.apple.Safari folder to the Trash.

Try Safari.

~ (Tilde) character represents the Home folder.

Which website? Or all of them?

Check Safari > Preferences - Extensions. If you have any installed, turn that off, quit then relaunch Safari to test.

If it's not an Extension causing the page issue, go to Safari > Preferences then select the security tab.

Deselect: Enable plug-ins

Quit then relaunch Safari. If pages don't "bounce" then you have a Safari third party add on installed that's causing the odd page behavior.

Troubleshooting helpe here > Safari: Unsupported third-party add-ons may cause Safari to unexpectedly quit or have performance issues

Bear in mind, it could be a plugin that does not affect Firefox.

Try moving all but one plugin to the Desktop.

Quit then relaunch Safari to test.

Process of elimination.

My money's on everything but the facebook plugin.