I had the same problem on my 701, and found the answer on the eeeuser.com wiki... It appears that the wifi does not work after 8.04.1 install... I will now quote the information that I found on that site...
Open a terminal window (Applications->Accessories->Terminal) and enter the following commands:
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sudo apt-get update
sudo apt-get install build-essential
wget 'http://snapshots.madwifi-project.org/madwifi-hal-0.10.5.6-current.tar.gz' (updated URL)
tar zxvf madwifi-hal-0.10.5.6-current.tar.gz
cd madwifi-hal-0.10.5.6-*/ (updated command; original did not append /)
make clean
make
sudo make install
sudo reboot
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The only problem that I had with this was the keyring wanting to control my every move... I deleted this file, and the system recreated another, but this one I set up properly... It will always require you to log-in, but wifi works A-OK!!
One last note from eeeuser.com... System updates (specifically new generic kernels) will reverse these changes; simply repeat the above to make your wifi work again...