Turning off tabs in safari?
How do I get rid of tabs in Safari on iPad?
iPad, iOS 5
How do I get rid of tabs in Safari on iPad?
iPad, iOS 5
I believe it's a built in feature, and you can't turn it off.
Safari on iOS 5 uses tabbed browsing, and not the thumbnail/page browsing as on previous iOS versions, and it can't be changed. If you want thumbnail browsing to be an option then you could try leaving feedback : http://www.apple.com/feedback/ipad.html
Turning off tabs in safari?