A series of newbieite questions

["ObeseWhale" <obesewhale@3dactionplanet.com>]

Hi, being a newbie to GNU/Linux I have a few questions...

1.  Debian keeps starting X as soon as I boot into linux.  It give me the
graphical login screen and everything.  This is annoying because I don't
seem to be capable of exiting X...  Is there any way to stop Debian from
running xdm on startup?

2.  My ethernet card, a Netgear fa310tx, came with a driver disk.  The disk
has a linux directory with but one file 'tulip.c', which is clearly the
driver...  How do I install this to get my ethernet card working?

3.  Is there any way to stop 8bpp as being the default color depth for X and
switch it to say, 16bpp.  I know I could startx using -- - 16bpp but I'm a
little lazy and just want 16bpp to be the default.

Thanks for all your help making my transition to the free software crusade
easier!