This repo contains the script install-rt8188cus.sh that installs and configures all the necessary tools for making a Raspberry Pi using a dongle that has a Realtek RTL8188CUS chipset into a wifi access point. I've used this along with PiUi SD card image (tutorial here). This is taken from this blog and modified to address some small gotchas (mentioned in the Notes section). Once the Raspberry Pi is set up, pull this repo down, and run
sudo chown root:root install-rtl8188cus.sh
sudo chmod 755 install-rtl8188cus.sh
sudo ./install-rtl8188cus.sh
You will the be prompted for some information in order to set up the Raspberry Pi as an access point.
Note that the script will perform a fetch in order to get a compatible hostapd binary that is compatible with the rtl driver. If that address (http://dl.dropbox.com/u/1663660/hostapd/hostapd) ever becomes broken, the hostapd in this repo can be used. It was downloaded from that address.
Make sure you use the correct wireless interface (e.g. wlan0, wlan1).
The hostapd binary will be in /usr/sbin/ after running the script. Place it into the correct directory (use which hostapd to find out the correct directory)
RTL8188 Access Point installation script - source of script
How to setup RTL8188CUS on RPi as an Access Point. - gives some detail of what happens inside script
PiUi Tutorial - How to set up a mobile phone UI accessible from a Raspberry Pi