I recently took action on this issue and encourage you all to do the same. The Federal Reserve is corrupt and needs to be abolished. Ron Paul has introduced legislation that would abolish the Fed. I urge you to contact your representatives and ask them to co-sponser and support this legislation.
There are several places you can do this at. If you have an account with DownSize DC you can do it here. This is what I use... they start you out with a few sentences and then you can add your own comments as you like.
Also the John Birch Society has a pre-written letter that you can send. All you have to do is provide your district information and it automatically sends it to your representatives. You can find this tool here.
If you want to write your letter all by yourself you can do that by using www.Congress.org . They have an easy to use set-up all you have to do is put in your zip code and you will get all your representatives contact information and you can choose to write any of them.