Since a lot of people (including me) are upgrading to Firefox 3.0, I thought I'd share a quick tip that I rediscovered on Patrick Cauldwell's Blog.  If you use Firefox (any version), it can drive you crazy trying to access internal network sites (specifically SharePoint sites in my case).  I end up having to log in every time I want to approve blog comments, access our internal project sites, etc.  I found this fix to enable NTLM so that Firefox will authenticate automatically like IE does.

1. Open Firefox
2. Type about:config in the address bar
3. Type network.automatic in the Filter bar
4. Right click network.automatic-ntlm-auth.trusted-uris and click Modify
5. Enter only the names of your internal servers in a comma-delimited list.  For example: [server1],[server2] and click okay.
6. Restart Firefox

You should be able to access all of your internal sites on the servers you entered through Firefox now without entering your name and password repeatedly.