I'm a bit of a noob myself, but I think it would help if you found where your flash drive is mounted first. It should be in the /dev directory. If you open My Places you should see it listed on the left hand side. Click on it, then right click, and then click properties. It should give you the location /dev/XXXX
Then run the command:
Replacing XXXX with the actual location.
You should get a listing like this:
Devices such as flash drives are simply files themselves so I would imagine that you could change the permissions using the command:
-r-xr-xr-x 1 root root 1000 Jul 11 10:20 file1
If you want write permissions you'll have to change the existing permissions. To do this you can use numbers as it's much faster.
So if I wanted write permissions for file1 I would run:
r or read = 4
w or write = 2
x or execute = 1
That's basically saying that with the first 7 I want to give the user (that would be me) rwx permissions. The second 7 gives the group (if there are other accounts on my system that are in the same group as me) rwx permissions. And finally the 5 would give everyone else, or Other, only r and x permissions.
You'll most likely need to do this as root so use:
Hope that helps