Alternatives are available as individual extensions and bookmarklets Bookmarklets are a lot easier on you your system] as you only invoke them when needed and they are very small. Google provided a list of alternative, or actually think mostly searches of extensions at addons, with a few specific extensions.

Firefox 4 is end of life, it is not supported.

see https://support.mozilla.com/en-US/questions/841081 for how to use the Google Toolbar with FF5 with support from neither Google nor Mozilla.

Unfortunately it has consequences of not being able to use Microsoft product email applications properly. As seen in a newsgroup without a reference a Google document. Which might explain why they are working on an Internet Explorer solution first.

Or continue reading Q841081 for alternatives, or a Google supplied list of alternatives at the very bottom.

I couldn't get the google toolbar with the new FireFox 5 so I went to tools and clicked downloads and found the older version of firefox so I uninstalled firefox 5 and reinstalled the older version and got my google toolbar back and now if I could just stop getting the pop ups to download firefox 5 all the time. Which I won't do because I like my google toolbar. Just wish I could rid myself of the firefox 5 download that keeps poping up on my screen. Or they could just fix the problem with the NO GOOGLE TOOLBAR WITH FIRFOX 5