You have to make an xorg.conf. If its ATI card, there is a command to generate your xorg.conf based on your current settings. Then you modify that file and its done.

Alternatively, you can use your catalyst or your nvidia control panel (just like windows) to make the changes.

If you are on an intel graphics chip, I'm not sure how to help you. No experience there. Sorry

Too little info to help you, my friend.

-What command?
-What distro?
-What DE/WM?
-Do you launch X via GDM or .xinitrc?

Hmm .. strange.
I thought Crunchbang had the proprietary Broadcom included by default.

Here's one possible solution. Worked for me (my netbook has a BCM4312, iirc) when I used CrunchBang in the past. At the time, I changed all my sources to point to Sid/Unstable, and my wireless broke as a result.

Make sure you're connected to a working internet connection (a wired one, obviously, since wireless doesn't work yet);

What I did was first purge (apt-get remove) firmware-b43-installer and firmware-b43-legacy-installer, then reboot...
Then I installed install firmware-b43-lpphy-installer. (apt-get install). The Lipphy driver will proceed to download some drivers from an external site (broadcom's servers, probably). Then reboot again....
If it works, you should have working wireless after this.

One downside to this;
For some unknown reason, my wireless signal strength in Conky maxed out at 70%, despite my wireless client (I used wicd-curses) telling me it was 100%. ... weird, but it still worked fine.

Sorry it didn't work out.

Have you checked out the Debian Wiki.
Specifically this: http://wiki.debian.org/wl#Squeeze
That part's for Squeeze, btw (what Crunchbang is based on out of the box) .... you'll need to read up a bit more if you've changed your sources to Wheezy or Sid.