Norton says that they will have updated versions of their Firefox extensions available in May.

Thank you, the- edmeister,

 I really don't like the new Fire Fox 4.0  I really hate not having the NORTON TOOL BAR for  the kids, I felt  the NORTON TOOL BAR  was a better choice when kids were researching anything on the web..... I look forward to the Norton Tool Bar extension in MAY.......
:) Dragonfly1305

I honestly don't think that Norton Toolbar extension has anything that isn't already built into Firefox, but then again I won't even consider installing the free-for-sales-associates version of NIS or 360 that is offered to me every year as part of Symantec's retail store promo for the new versions (never installed it though, so I can't say for sure, but based upon the literature with it I'm pretty sure I am close).

Norton has a fix. See: http://community.norton.com/t5/Norton-Internet-Security-Norton/Norton-Toolbar-5-5-incompatible-with-Firefox-4-RC1/td-p/411556/page/2

I have comcast, sooo my NORTON security suite has to catch up to 2011 version in order for the tool bar to work :/ it should be up dated by this summer. thanks  ;)