This is a very simple task.
Once you created the Static Block, simply go to CMS -> Manage Pages. Select your Page or create a new one.
Click on the Design tab on the left and paste the following code to the “Layout Update XML” textarea.
(Also, don’t forget to select the Layout, eg.: 2 columns with left (or right) bar)
<reference name="left"> <block before="-" name="block-name" type="cms/block"> <action method="setBlockId"><block_id>block-id</block_id></action> </block> </reference>