Huh?  RedHat is not an ISP. You can use any "normal" ISP that supports PPP.  What ISP do you normally use?  Netzero will probably not work.  The last time I used them they only had a proprietary Windows dialer.  Same goes for AOL.  And I would never use MSN, but I would assume since it is owned by Microsoft that you would never be able to dial into their network without a Windows based client, but that is an assumption, I do not know that to be fact.