As found via ROBS BLOG Google released Beta of Google Toolbar v3
New version of Google Toolbar adds spell checker for forms, a translation tool and a feature to auto-link U.S. postal addresses to maps (Google Maps, MapQuest or Yahoo Maps)
For me, the spell checker is absolutely the most useful new feature in v3. Andrew Sutton some time ago posted recommendation of a great tool ieSpell that adds spell checker feature into IE. Now I can uninstall ieSpell as this feature comes with the G' Toolbar.
As a used to be a 100% Internet Explorer user, nowadays I use both IE and Mozilla Firefox (about 50/50) so the new Google Toolbar features come very handy for me.