Web development in IE just got a whole lot better (well, at least for me).

Enter Microsoft's Internet Explorer Developer Toolbar (link).

This is one area where IE has been just left behind in the dust by FireFox.  But this is definitely a nifty add-on!

Just a short outline of the features:

• Built in validation from a dropdown.  Nifty and convenient.
• Built in onscreen ruler!  This is awesome.
• Ability to quickly resize the window.
• DOM browser like FireFox.

And a ton of other stuff.

If you make webpages for a living, then all I can say is: Must. Download. Now!

Note that after installing it, you have to enable it by selecting it from the View->Toolbars menu item (it's instinctive to look in the Tools menu and get baffled by the lack of new menu items).

Update: there's also a non-Microsoft, FireFox analogue.