The Tab Scope Firefox plug-in lets you preview tabs live just by hovering your mouse over them. The view is just like Vista’s, so you can see what’s going on in other open tabs without changing tabs.
Tab Scope also includes reload, refresh, and stop buttons in each preview window. When a preview is highlighted you can even scroll within the tab. Tab Scope can be downloaded for free.
Remember, you can move tabs in between separate Firefox windows.