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...
A. Nicholson, and B. Noble. Proceedings of the 14th ACM International Conference on Mobile Computing and Networking, page 46--57. New York, NY, USA, ACM, (2008)
H. Liu, Y. Gan, J. Yang, S. Sidhom, Y. Wang, Y. Chen, and F. Ye. Proceedings of the 18th Annual International Conference on Mobile Computing and Networking, page 305--316. New York, NY, USA, ACM, (2012)