Is there any recommended plugin to display pages how they look in different browsers? I found one which opens the same page in IE but wondered if there was anything better, like one which formats the page within Firefox The one i installed was called IE tab
They're called 'add-ons' or 'extensions'. Plugins are an entirely different animal. What you want for IE is IETab. I don't know if there is one for Opera but that's why there is a Firefox Add-On page to search through, plus search is built into Firefox under Tools->Add-Ons. For Opera, it would be good just to install it.