On problem with Firefox that enterprises commonly report is that there is no easy way to tell Firefox that http://name is a URL on your intranet. Firefox will go through the normal process of attempting to add www and com to the name and it will fail. I think I've found a solution.
The default prefix and suffix that Firefox uses to "fix up" the URL can be specified. The defaults are "www." for the prefix and ".com" for the suffix.
You can change the prefix with the preference browser.fixup.alternate.prefix and you can change the suffix with the preference browser.fixup.alternate.suffix. So to make this work for your company, change the prefix to an empty string and change the suffix to .yourcompanyname.com. Don't forget the "." at the beginning of your domain.
With that change, typing in http://foo will go to http://foo.yourcompanyname.com.