I will be watching this subject also as I am giving an older laptop to
the grand kids
to use on there parents wifi network, under supervision. But another
question is, are
there any USB wifi adapters that work good. The one I tried several
years ago was
not very good and kept loosing connection. Maybe there have been
improvements.

This website was posted some time ago:

http://linuxwireless.org/en/users/Devices/USB

It contains most of the Linux compatible Wifi/Usb devices.

I personally use the TP-Link ones. They work right out of the box.

One question, these USB wireless devices, are they for services
like offered from cell phone companies or for home WiFi networks,
or either/both?

You can get both but the one cell providers offer are costly...

Cell phone devices are typically called 3g or 4g devices. You may find
the memory that holds the drivers for
Windows gets in the way of Linux being able to discover the actual
device. If you see a memory device but can't find the phone device it is
likely the memory is getting in the way. Unmount the memory device and
the broadband card will show up.

Wifi is another device type. Depending on the chip set the drivers will
be self installed or not. Broadcom chip sets will likely need to be
installed, and require a Internet connection to do so. This can be a
broadband phone card or lan connection.

Fortunately, this is changing. My Broadcom-equipped laptop was online "out of
the box" with the latest versions of Ubuntu, Kubuntu and Mint, and even Puppy.

This is good to know. I do wonder why I have had to let the machines I
have installed 11.10 on, be connected to the Internet when installing to
get the Broadcom built in WiFi cards to work. I have a USB WiFi card I
use to set people up. Without it WiFi using Broadcom has been a problem.
My guess is because of the proprietary nature of the drivers.

So you are not connected to the Internet in any other way and you get
them to work? That is cool.

My HP G62 laptop has a BCM 4313 rev 01 PCI wireless adapter. When I first
installed Ubuntu in the summer of 2010, I had to use Ethernet to my router to
install the Wireless driver.

This fall I have done clean installs of Ubuntu, Kubuntu, Mint and Puppy without
ever using an Ethernet cable. Just have to enter the WPA key, and Bob's Your
Uncle. (I installed the last two on flash drives, yes real installs.)

g> This fall I have done clean installs of Ubuntu, Kubuntu, Mint and
g> Puppy without ever using an Ethernet cable.

Every new version of Ubuntu ( and most other distros too ) adds more
and more hardware compatibility in. Who knows, in a few years we all
might be out of a job and have nothing much to talk about

Most adapters are plug and go, the only ones that may prove a bit more
of a challenge are those with Broadcom chipset. but even those tend
to be fixed after an update via cable ( does mean running an ethernet
cable temporarily ).

The Linux Compatibility List site is a good place to go for all sorts
of hardware questions - http://linuxhcl.com/ and you can specify
Ubuntu in the search too.

Personally I've found ZyXel USB adapters to be reliable and 'just
work'.

One point to mention - Wireless 'N' adapters are more of an issue than
the 'G' ones but you do tend to get a greater range with them. Depends
on the distance between router and PC whether you need to consider 'N'
devices.

Another option to consider for a fixed PC is ethernet over mains
units. These are pretty good and have used these quite a bit too in
situations where wireless is a problem.

I was pleasantly surprised recently when I installed Xubuntu 10.10 on an
HP PC. I had attached a Linksys WUSB100 USB Wireless adapter before
when it was running XP.
It automatically installed driver for it and usually comes up connecting
to my D-Link Wireless N router at 130 to 150 Mbs. It could not have
been easier and it connects
at a high data rate.

I have gotten very good results from a TB-Link TL-WN822N USB adapter on my
Mythbuntu system. The system gets its video feed from ethernet-connected HD
HomeRun tuners.

Another option may be ethernet-over-power-line adapters if your computer has an
ethernet jack. I think it may offer more bandwidth than the USB adapter. We
are using a pair of these to connect our TV to the router. These devices can be
sensitive to which phase of the power line they are on.