I searched around for some time trying to get an explanation on how to get the Belkin N Wireless USB Adapter (F5D8053) to work in Ubuntu 9.10 (karmic). I had tried several times to get the native ralink driver working, but to no avail. This afternoon I managed it, and so I thought I would share what I'd learned, as there seemed to a good few others with similar problems.

Get the driver from Ralink
Visit and download RT2870USB(RT2870/RT2770). The version I used was Extract the downloaded driver (RT2870_LinuxSTA_V2.3.0.0.tar.tar.bz2) and cd into the directory:
george@transistor:~$ tar xfj RT2870_LinuxSTA_V2.3.0.0.tar.tar.bz2 
george@transistor:~$ cd RT2870_LinuxSTA_V2.3.0.0/
Configure the Driver
Next we must configure the driver, as explained in README_STA:
george@transistor:~/RT2870_LinuxSTA_V2.3.0.0$ nano os/linux/
We must edit two options - Find these two options:
... and change them to
Use CTRL+X to exit, answering Y to save changes, and ENTER to use the original filename.

Compile & Install the Driver
Next I compiled the driver. You will need to install build-essential and kernel headers. Im pretty sure thats all you need, but I am unsure. I had already installed them a long time ago.
george@transistor:~/RT2870_LinuxSTA_V2.3.0.0$ sudo apt-get install build-essential linux-headers-generic
george@transistor:~/RT2870_LinuxSTA_V2.3.0.0$ make
Once make finishes (if it errors, you will need to fix this first of course - it compiled first time for me) you need to install the drivers. This must be done as root, and is done as follows:
george@transistor:~/RT2870_LinuxSTA_V2.3.0.0$ sudo make install
[sudo] password for george: <USER PASSWORD HERE>
Blacklist the old drivers & force use of the new ones
To force the use of the compiled driver, called rt2870sta, you need to blacklist the ones loaded Karmic as default. To do this, enter the following command:
george@transistor:~$ sudo nano /etc/modprobe.d/blacklist-rtusb.conf
This opens the nano text editor as before. Add the following to the file /etc/modprobe.d/blacklist-rtusb.conf
# Blacklist the default usb drivers for rslink card
blacklist rt2500usb
blacklist rt2800usb
Use CTRL+X to exit, answering Y to save changes, and ENTER to use the original filename.

The simplest thing to do at this point is reboot. If you know what you're doing, you can easily use modprobe to remove the default modules and to insert the newly compiled module into the kernel. Something like the below:

modprobe -r rt2500usb rt2800usb
modprobe -i rt2870sta
It works
george@transistor:~$ lsmod | grep rt2870
Module                  Size  Used by
rt2870sta             624696  1