Plug-in Recommendation needed for Ad-friendly blog

I’m not putting ads or Adsense on my blog right now, but I intend to in the future. I’m looking for some recommendations for plug-ins which would allow my blog to place and post advertisements smoothly along the right or left column of a 3-column blog. Any plug-in suggestions would be appreciated, and if you can refer me to some sites with those plug-ins being utilized, that’d be great too.