IE9 arrives, but not for XP

Here's what's hot this week in Windows downloads.

Microsoft has taken the training wheels off of Internet Explorer 9, debuting a full-featured browser that has proven to be the fastest, most standards-compliant IE version yet. There's a catch, though: IE 9's not for Windows XP. You'll need Windows 7 or Vista if you want this browser.

And if you're a Microsoft Outlook user prone to rash e-mailing, you might want to check out ToneCheck from Lymbix. This e-mail sentiment analysis app monitors your e-mail's composing window for potential errors of tone, just as spell-check scans for errors of spelling or grammar.

Finally, for the Firefox fans, it looks like Mozilla has buttoned up Firefox 4; the features are locked, and barring the discovery of any major bugs, this version is likely to become the browser's official release. Release Candidate 1 is available for download now.