The procedure to activate rtl8139 on linux is as follows:

  step 1: ftp the driver from
	 	ftp://cesdis.gsfc.nasa.gov/pub/linux/drivers/rtl8139.c

  step 2: compile:
           The instruction for compiling the driver is include at the
           end of the driver file. (run this instruction at
           /usr/src/linux)

  step 3: insert the driver as module:
           insmod rtl8139.o
        parameter can be added by adding options=..... behind the istrruction
                0x16(bit 4):full duplex
                bit 0-3    :default port
        (run 'lsmod' to see if the module is inserted)

  step 4: bind your card to an IP address

     /sbin/ifconfig eth0 ${IPADDR} broadcast ${BROADCAST} netmask ${NETMASK}
        (run 'netstat -i' to see if there is a interface 'ne0')

  step 5: add your card to IP routing table, then add gateway also
     your card:
	   /sbin/route add -net ${NETWORK} netmask ${NETMASK} eth0
           (should be able to ping local network now)
     gateway:
           /sbin/route add default gw ${GATEWAY} netmask 0.0.0.0 metric 1

  step 6: start inet deamon.
           /usr/sbin/inetd
           (you are on the network now)

*make sure that your kernel is built with network, fast_ethernet and module
 support. Otherwise, you have to rebuild your kernel.
 	(1:go to /usr/src/linux directory
         2:run 'make menuconfig' or 'make config'
         3:mark the options list above.
         4:exit and rebuild your kernel.
            make dep;make clean;make zImage
           the file 'zImage' will be at /usr/src/linux/arch/i386/boot/zImage
         5:modify /etc/lilo.conf.(this file specify where kernel image is)
         6:run 'lilo'  )

You cna run 'netconfig' which will do step 4,5,6 for you. This will create
'/etc/rc.d/inet1' and 'inet2' files. These two files will run at boot time.
Then just add a line at the beginning of 'inet1'.
        'insmod /your driver'path/rtl8139.o'

then your driver will work every time you boot.