I followed the instructions on ndiswrapper installation wiki. I need a little clarification on a few parts though, as I'm somewhat new to Linux. After I make the link from the source, the instructions say "Make sure you have started compiling the kernel sources, so needed header files are present."
How exactly do I do that? Also, when you go to compile and install it.. "Go to source-directory and run 'make distclean' and 'make'. As root run 'make install'." Is it referring to the kernal source directory? Do I run all three of those commands from the kernel source directory? Sorry I'm still learning.

To get mine running I did this in suse 10.
No kernel stuff required.

Copied my win drivers to a new, empty folder.
Made sure I was in that folder to issue commands as root.

ndiswrapper -l[lists installed drivers]
ndiswrapper -i FILE.INF [win INF file]
ndiswrapper -m [loads driver]
modprobe ndiswrapper [reloads ndiswrapper module]

You also need wpa_supplicant for wpa encryption.

Then configured the card.
good luck

I assume that you have the kernel-source installed. If you have an RPM based system, there will be a kernel-source package for your kernel.

If you have a kernel-syms or kernel-symbols package, then you don't need to start compiling the kernel.

There may also be further instructions in the kernel source regarding installing kernels. Look for a README file in /usr/src/linux. There may also be a README.<distroname> readme file as well.

Take a look at the /var/lib/`uname -r` directory.
# ls /lib/modules/2.6.16.13-4-default/
build modules.alias modules.ieee1394map modules.ofmap modules.symbols source
kernel modules.ccwmap modules.inputmap modules.pcimap modules.unsupported updates
misc modules.dep modules.isapnpmap modules.seriomap modules.usbmap

Is there a build/ link there?
ls -l /lib/modules/`uname -r`/build
lrwxrwxrwx 1 root root 45 2006-05-21 07:31 /lib/modules/2.6.16.13-4-default/build -> /usr/src/linux-2.6.16.13-4-obj/x86_64/default

If so, I don't think that you need to start building the kernel.

Good luck!

I've got the driver installed. When I do ndiswrapper -l, it says that the driver is installed and the device is present. It's not showing up as wlan0 though so I can't configure it. How do you configure it for wlan0? Also when I've tried to modprobe ndiswrapper I get a 'module not found' error.

The "ndiswrapper -m" step installs an alias, so wlan0 is the name you would normally see.

You may be confusing the wrapping phase, with loading in the kernel module.
Doing "modprobe ndiswrapper" as root should load in the ndiswrapper.ko module. If not, then you may not have the correct kernel module for you kernel and it was installed in the wrong directory. For example, if you had upgraded the kernel during a security upgrade, and only now rebooted, then you now have a different running kernel.

Which distro do you have? It might help if we knew that. ( You should put that in your profile so that we don't have to ask ).

If you have SuSE, Mandriva, Red Hat, or another RPM based distro, you could build the Ndiswrapper program and driver using RPM build. The source is build so that you can do that. The wiki on this site has the instructions.

This is the way that I do it because
A) The SuSE 10.1 ndiswrapper package didn't work for me so I reverted to an earlier version from source that did.
B) I leave the ndiswrapper.spec file in the SPECS directory and the source tarball in the SOURCES directory, so if I just updated the kernel, I can run "rpmbuild -bb ndiswrapper.spec" to build a new ndiswrapper-kernel-module (RPM file) which I install using the rpm command.

Ah, I see. I'm using Slackware 10.2 right now, fresh install.

Slackware isn't RPM based. You need to keep the source handy and use the make target to remake the kernel module whenever you upgrade the kernel.

The module not found error means that the "ndiswrapper.ko" file isn't installed or is installed in the the wrong place.

I don't know if Slackware has something like a kernel-syms package that will set up a /lib/modules/`uname -r`/build/' environment and install the kernel symbol tables that would exist had you made the kernel yourself. This is a cheat that saves a lot of work that a number of distros use ( Mandriva and SuSE for example ).
Look under /lib/modules/ or /lib/modules/`uname -r` or /lib/modules/`uname -r`/build/ for a README file or a README.slackware file. It may explain a lot.

Examine the contents of the Makefile. There should be a target to make and install just kernel module and not the command itself. If you did a make install already, then the \usr\sbin\ndiswrapper command is already installed.

I think that it should be installed under /lib/modules/`uname -r`/kernel/extras/'. But my memory may have failed me. The `uname -r` part is the kernel version, and what the "uname -r" command returns. That is the part that may be different now from when you installed ndiswrapper.

Cd to /lib/modules, and use the find command to locate the kernel module.
"find ./ -iname "ndiswrapper*"
compare the kernel version where

However, there are a couple of commands you can try that may have been aborted during the installation that you can try now:
depmod -a
ldconfig

The ndiswrapper installation should have run these.

You are still a step before the wlan0 interface will show up anywhere.