The latest "downlevel" firebug uses the pi debugger. I'm just upgrading now...could be a good alternative for Google Chrome debugging as well as IE.

Quoted: Get Wired's take on technology business news and the Silicon Valley scene including IT, media, mobility, broadband, video, design, security, software, networking and internet startups on Wired.com

IE has a subtle bug when parsing array constants - I think they are not in conformance with the ECMA-262 spec.

You can test your browser here:

http://pages.mckoss.com/dangle.htm

Update: Object initializers are even worse! Fails to parse the JS at all.

Firebug-clone for IE (from Microsoft)

Quoted: The Microsoft Internet Explorer Developer Toolbar provides a variety of tools for quickly creating, understanding, and troubleshooting Web pages.

On a brand new machine, running IE 7.0.6000.16643, when I open a new tab, I get the "You've opened a new tab" page - but it HANGS/CRASHES IE (that page is non-responsive for about a minute!). I can't navigate to another page, or click the close button, or the close box, or anything.

Here's a trick to nuke this stupid page and just get a blank page when you open a new tab:

Run: regedit
Navigate to:
HKEY_CURRENT_USER \ Software \ Microsoft \ Internet Explorer \ TabbedBrowsing
New DWORD: ShowTabsWelcome = 0

Resart IE, and this annoying (and buggy) page is gone.

IE8 supports client-side debugging with a feature that looks identical to Firebug - yeah!

Nice description of new IE8 features in Beta 1.

IE 8 Beta 1 available for download.

Quoted: Download the Internet Explorer Beta. It's designed to help developers and designers prepare sites for Internet Explorer 8.

Instructions on using TweakPNG to remove the gAMA information.

Quoted: Tutorial Description: There’s been a problem that has plagued the PNG world for years. Few people ever figure out why PNGs appear darker in IE and didn't match CSS colors... but there is a solution! Read this easy-to-follow guide to find your way out of this nightmare!