See the PowerPoint file on left for some MU Health Care templates & examples.
For additional ideas, you can always Google "science poster templates". Many other universities have templates as well.
MakeSigns.com has templates online. (They hope you'll use them as your printer.) This is a good site to get examples of poster sizes as well as what works & what doesn't! http://www.makesigns.com/SciPosters_Templates.aspx