5. Finding more info
 | I can't stress it enough, the documentation that comes with your hardware is the Ultimate Reference. |
Aside from that:
The Linux Documentation Project and its collection of howtos.
The Hardware Howto lists Linux-compatible hardware.
The Plug-and-Play Howto sometimes a bit thick, but good info.
The specific Howtos: networking, graphics cards, etc...
The Debian-User mailing list and its archives. You can search the archives there