I have heard these problems a lot from others.... however DSL and linux works fine, but it are the crappy USB modems that are the problem... or at least the lack of support / drivers for those. I advice everyone to buy a modem or router with ethernet port to connect to your lan or pc (for instance the 'speedtouch home' or pro from Alcatel, not the speedtouch USB offcourse). You will need (an extra) network card but it will work no matter what OS you are using. Even PPPoE is available for most OS's. The prog and drivers for Windows and Mac OS can usualy be found on the CD that comes with the modem and for linux you can use http://www.roaringpenguin.com/pppoe/

Perhaps RedHat 8 has better support for those devices. I heard good news about the new redhat release but I can't confirm that already.