Oh, and the reason why they don't work, is because you've most likely have your client updated to 2.4, and currently the two biggest binary distributors (mangos and ascent/antrix) haven't updated to 2.4 yet. So, unless someone was able to make their own updates by themselves, you will not find a working private server until the binaries are updated to support the current client version.
You can get a good wow private server here.. WWW.XTREMETOP100.COM
Try Underworld or Mirandas wow.
Its fun and different; You can level to 255 ETC:.
*NOTE* Most private servers are NOT up to date on the new patch..
You'll have to find a server that is.. or, Delete the patch.