Ok. There's some good information here.
I'm in the office now, and can only help a little, so I'm going to try to point you in the right direction(s), and ask you to do just a little research on your own.
That's in the spirit of "teaching a man to fish" instead of giving him a fish. ;>
The ps command is used to tell you what's running. The output from that command was used as input to the grep command when you typed >ps -el | grep dh. Grep tried to match the string "dh" and returned only the matches. So, it told you that dhcdbd is running, but not dhclient.
I looked up dhcdbd, and found: "dhcdbd provides a D-Bus interface to dhclient, the DHCP client from ISC, so applications such as NetworkManager can query and control dhclient".
It looks to me that you need to install and start dhclient.
Can you do that? I'm running Mandriva, myself, and the details will be different. But I'm sure that's it's available to you (perhaps through some sort of control-panal type of application that you can run to install other programs from a repository). When it's installed, you just type (as root) >dhclient wlan0 (and that's because your pc knows that you have a card installed, and is calling it wlan0).
There will be one more step, and that's to make dhclient start when you boot up (assuming you want it that way - most people do). I'll have to look up the details, because I don't want to give you the wrong file or location of the file. But essentially, you'll be adding one line to a configuration file, and that's all.
But that step, and the ones I'm about to mention may be taken care of for you automagically if (and only if) Ubuntu provides you with some sort of network configuration tool like Mandriva does. Sorry - I'm ignorant about that, but it would be worth you poking around in both your PC for something that looks like that and to poke around in the Ubuntu forums for that info.
When that is done, then you're almost home.
As root type >ifconfig wlan0 down
>ifconfig essid "<your essid here>"
>ifconfig wlan0 up
The ifconfig command (with no parameters) gave you
wlan0 Link encap:Ethernet HWaddr 00:19:5B:3A:0B:AC
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:3 errors:0 dropped:0 overruns:0 frame:0
TX packets:23 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:276 (276.0 b) TX bytes:4351 (4.2 KB)
before, which says that you're card is recognized (and gives the MAC address as 00:19:5B:3A:0B:AC), and is broadcasting. (but not hearing anything much, btw). It's saying that your card is recognized and is trying to work.
The iwconfig command (with no parameters) says that you haven't "associated" with your router, which is because the dhcp protocol didn't do it's thing (because dhclient wasn't running).
Oh! I just realized, your router
needs to be running dhcp for that to work too. Otherwise you need to research "static IP addresses" and find out how that's set up in Ubuntu! Hummm. If you have a choice, you probably want your router to use dhcp - that's dynamic addressing. It'll be easier in the long run.
The iwlist wlan0 scan command is not returning what I expected. I think that may have been because of dhclient not running, but I'm not sure.
When you have an association with your router, the output will look something like:
wlan0 Scan completed :
Cell 01 - Address: 00:06:25:E8:3A:05
Frequency:2.437 GHz (Channel 6)
Quality=37/94 Signal level=-58 dBm Noise level=-95 dBm
Bit Rate:1 Mb/s
Bit Rate:2 Mb/s
Bit Rate:5.5 Mb/s
Bit Rate:11 Mb/s
Bit Rate:18 Mb/s
Bit Rate:24 Mb/s
Bit Rate:36 Mb/s
Bit Rate:54 Mb/s
Bit Rate:6 Mb/s
Bit Rate:9 Mb/s
Bit Rate:12 Mb/s
Bit Rate:48 Mb/s
(or, at least, it should).
Ok - Your mission, should you decide to accept, is to find out if and how Ubuntu manages your network. Should you succeed, the DA will definitely disavow all knowledge of your activities ;>