I was recently asked about my small collection of social badges on the top of my blog in the sidebar. These are created by the excellent WordPress plugin SocialGrid:
I have a few WordPress.com sites but used this one I set up for some WordPress.com training courses put on by OutserveWeb the web training company I work for. The end result looked like this and I have put the code below if it helps anyone.
Change the links and the image urls of course and copy the code into the text widget and drag to your sidebar, images can be uploaded directly through the Media options in your WordPress.com blog. It should be relatively easy to change the grid from 2 x 4 or use other or different size icons.