the ubuntu package manager is called apt-get
if the pagages exist in your defiened repositories the following commands should install madwifi and wine
apt-get install wine
apt-get install madwifi
Wine is a package for running windows software under linux. If you want to use windows drivers for your wifi card you will want to use ndiswrapper instead.
madwifi is for athereos wireless cards that are not supported by the open source ath5k and ath9k drivers. make sure your wireless card's model number is not supported by these open source alternatives as madwifi can be very dificult to get set up properly but the open source alternatives are not.
If you are just switching from windows to ubuntu there is an interesting set of articles concerning this exact situation published by the folks at Ubuntu. You can find these articles here
For general Ubuntu help and getting started guides Ubuntu has published an excelent and comprenensive set of documentation designed to get the uninitiated up and running fast and provide vast amounts of information to those trying to learn more about the distrobution and how to use it. If you have the time i would definitely recommend taking a gander at them. the official documentation for 9.04 may be located here and the community contributed documentation is available here
It is also worth mentioning that an additional and more targeted source for help may be the official Ubuntu forums. In addition to having a higher total traffic, the forums are dedicated to Ubuntu and it's derivatives and as such will often provide you with answers faster. The forums are free, just like us, and make an excellent additional resource. you can find the forums at http://www.ubuntuforums.org
If you are in a real hurry some help can also be found via google searches, but beware that the information found that way might be out of date or targeted at an entirely different issue.
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ArchLinux x86_64 - Custom Built Desktop
ArchLinux x86_64 - Compaq CQ50 Laptop
ArchLinux i686 - Acer Aspire One Netbook
ArchLinux i686 - Dell Presario ze2000 (w/ shattered LCD)
PuppyLinux, CloneZilla, PartedMagic, DBAN - rescue thumbdrives
Windows 7 (x86_64 desktop alternate boot)
