Wireless Not Recognised in Backtrack 3

Use  -  "airmon-ng stop ath0"
            "airmon-ng start ath0"

This will put the wireless card into monitor mode. You can also try wifi0 if ath0 does not work.
Or wlan0 etc...
Once that is successful open the wlan manager find an AP and connect......

First check which wifi chip you have and then follow instructions below:

The Intel 3945ABG wireless controller is found in the Centrino chipset and is quite common in Intel Core and Intel Core 2 systems.
http://www.linlap.com/wiki/Configuring+the+ipw3945+module+for+the+Intel+3945ABG+wireless+controller

The Intel 4965AGN wireless controller is found in the Santa Rosa chipset and is quite common in newer Intel Core 2 systems.
http://www.linlap.com/wiki/Configuring+the+iwl4965+driver+for+the+Intel+4965AGN+wireless+controller

I dont have an ath0 or wifi0 or wlan0. It's not a configuration problem. I'm pretty sure it's a driver thing. How can I find out what the chipset is? And backtrack is not in the linux list in the guides. Which linux is the closest to backtrack?

It is a driver thing as I also confirmed on my earlier post.  Check your laptop's bottom for the model number (there should be sticker) and type it in google, or tell it for us here and we will check it out.

I think what you're looking for is 1505, not 3945ABG or 4965AGN.

According to this site below there is atleast 6 different wifi chips used for the D830. Thats quite lot :-)

 http://www1.euro.dell.com/content/products/productdetails.aspx/latit_d830?c=ed&l=en&s=bsd&~tab=specstab

Note from the site I pasted earlier :

"If you haven't purchased the D830 yet try and get it with the Intel 3945ABG wireless controller. The versions with the 4965AGN and the Dell 1390/1490 are harder to get working."

Thought it doesnt mention 1505 at all.  Anyways I did more searching nd the driver can be downloaded from: http://www.broadcom.com/support/802.11/linux_sta.php

Installation instructions are found from here:
http://www.broadcom.com/docs/linux_sta/README.txt

Thought this installation requires medium or good knowledge of Linux OS.  There is no easy way for this unfortunately :-(

While trying to search suitable solution for you we havent even asked about the most important matter, what Linux Distribution you are running at the moment? :-)

FINAL WORD: This driver is included in the Ubuntu 8.10 release and newer. AFAIK Ubuntu is at the moment one of the easiest Linux Desktop Distribution and it has quite good driver support. You could check it out.

I checked the link and in the connectivity section, under WLAN you can see Dell Wireless 1505 802.11a/g/Draft?

I have been using linux for a while so I think I can figure it out. Never installed drivers and that was the reason I never started using linux permanently, driver issues...

Last of all, the Linux Distribution, as I metioned in the message AND in the title:)), is BackTrack 3.0. I think it's built on Slackware. I dont want to use another distribution, I need this one for penetration testing.

So I wouldnt need drivers with VMWare? And can I do everything I could normally do with VMWare? Fake my mac address for example?

You dont need drivers with VMware as the network is handled by the host system (which is Windows in this case). VMware supports  atleast following network settings:

Private NAT
Bridged (your VMware host gets own IP from the same network)
Shared IP

I assume that faking mac address with Bridged mode should be OK.  

You can run VMware OS as you run anything else OS on your system, just give it enought CPU,RAM, and HDD and it will run smoothly.

If you have spare HDD (or windows allready installed on some D830) you could install VMware workstation demo and try it out with BT3 image.

VMware Workstation can be downloaded from:
http://www.vmware.com/products/ws/

BT 3 VMware image from:
http://www.remote-exploit.org/cgi-bin/fileget?version=bt3-vm

Happy hunting! :-)

You've been really helpful. Thanks a lot:)