In Ubuntu 10.04, it seems extremely easy to have this hostapd work. First, of course, you need to install it. It is already in the official repositories. Just run this in the terminal:
sudo apt-get install hostapd
Then, open a text editor program, for example gedit. Copy the following into it.
interface=wlan0
driver=nl80211
ssid=
channel=1
hw_mode=g
auth_algs=1
wpa=3
wpa_passphrase=
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP CCMP
rsn_pairwise=CCMP
driver=nl80211
ssid=
channel=1
hw_mode=g
auth_algs=1
wpa=3
wpa_passphrase=
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP CCMP
rsn_pairwise=CCMP
Please don't forget to fill in the name of your network after "ssid=", as well as the password after "wpa_passphrase=".
After all these, save the file as hostapd.conf in your home folder.
Now, in your terminal:
sudo hostapd hostapd.conf
Turn the wifi connection on in your devices and enjoy the fast network share!