I'll answer the first part of your message, and give a few hints on
the second..

The 3c905b is not completely hardware compatible with the 3c905, so
the driver for the 905 (which is supported on 1.3.2) cannot be used
with the newer '905b.

NetBSD-current contains a new "ex*" driver for the 905b, which should
appear in 1.4 when it's released.

   Because the ethenet card can not function properly, so I change to another
   type ethernet card:

   Intel EthenetExpress PRO/100B PCI Ethenet card.

I'm not directly familiar with this card; the following suggestions
are generic to any ethernet card.

   the card is properly detected and device  is: fxp0
   however when I use it to install the netbsd via network, it does not 
   work( I mean, when I choose ftp to install, after I enter, there has no 
   response , I wait a long time, and the network card is working from the 
   indicator light). I have no idea about it. 

   The IP and other network configute data should be correct. If you
   know the problem, Please e-mail me. Great thanks

A number of problems could manifest themselves in this way; we'd need
more information to diagnose this.

You may want to poke around a little bit in the single-user shell you
get when you exit from sysinst..

A few things to try:
 - what media options are configured on the fxp0?  (see the output of
"ifconfig -m fxp0"); does this match the network that it's plugged
into?

 - can you ping the system to be installed from another system on the
same subnet? from a different subnet?
 - is the nameserver information correct?
 - can you see outbound traffic from the system using tcpdump on
another system?

					- Bill