Follow these steps to compile the 8188eu driver by yourself

 1. Enable "install & update kernel headers" in the raspbmc settings menu => system configuration (this will take a while, you wont see the progress)
 ⇒ needed for grabbing Module.symvers

 2. Install GCC, MAKE and GIT
 pi@raspbmc:~$ sudo apt-get -y install gcc make git

 3. Get linux source code
 => Please verify that you are at ~ which is equal to /home/pi !

 pi@raspbmc:~$ wget --no-check-certificate https://github.com/raspberrypi/linux/archive/rpi-3.10.y.tar.gz

 pi@raspbmc:~$ tar -xzf rpi-3.10.y.tar.gz
 pi@raspbmc:~$ mv linux-rpi-3.10.y rpi-linux

 4. Get rtl8188eu source code
 pi@raspbmc:~$ git clone git://github.com/lwfinger/rtl8188eu.git

 5. Clean the kernel source
 pi@raspbmc:~$ cd rpi-linux
 pi@raspbmc:~/rpi-linux$ make mrproper

 6. Setup .config and clear the CONFIG_CROSS_COMPILE assignment in .config
 pi@raspbmc:~/rpi-linux$ zcat /proc/config.gz > .config
 pi@raspbmc:~/rpi-linux$ vi .config

 6.1. Now clear the CONFIG_CROSS_COMPILE assignment ⇒ CONFIG_CROSS_COMPILE=""
 6.2. Type ":x" and then type Enter to save

 7. Prepare the modules
 pi@raspbmc:~/rpi-linux$ make modules_prepare

 8. Copy Module.symvers from kernel headers folder to linux source folder
 pi@raspbmc:~/rpi-linux$ cp /usr/src/linux-headers-3.10.13/Module.symvers .

 9. Prepare the installation of the rtl8188eu driver by defining folder links
 pi@raspbmc:~/rpi-linux$ ln -s /home/pi/rpi-linux /usr/src/linux
 pi@raspbmc:~/rpi-linux$ ln -s /usr/src/linux /lib/modules/3.10.13/source
 pi@raspbmc:~/rpi-linux$ ln -s /usr/src/linux /lib/modules/3.10.13/build

 10. make and install the rtl8188eu
 pi@raspbmc:~/rpi-linux$ cd ../rtl8188eu
 pi@raspbmc:~/rtl8188eu$ make && make install

 11. Optional: Install the driver if make install didn’t work due to permission
 pi@raspbmc:~/rtl8188eu$ sudo cp 8188eu.ko /lib/modules/`uname -r`/kernel/drivers/net/wireless/
 pi@raspbmc:~/rtl8188eu$ sudo depmod -a
 pi@raspbmc:~/rtl8188eu$ sudo modprobe 8188eu

 12. now ifconfig should show wlan0