Google adds RSS feed integration with the Google Personalized Homepage and improves search functionality with:

• Previous queries
• Spell checking
• Suggestions

It also catches mailto: links and opens them in Gmail instead of a desktop email client. That’s good for me, because I use Gmail and it has been trying to open in Outlook (which I don’t use).

“As a dedicated Firefox user, I think that the latest version enhances an already innovative browser. Meanwhile, you IE Toolbar 4 fans may notice that the feature sets aren’t identical. That’s because Firefox and IE users have different needs,” said Google software engineer Justin Voskuhl. “Rest assured that we’re working to get the most popular features in both versions.”

via betanews

Update: Google also blogged this officially in Justin’s post titled “Toolbar v2 for Firefox fans”.