For a Poster Presentation, there are several programs you can use – the most popular, but probably not the best is Microsoft PowerPoint. Others that are nice are Adobe Illustrator or In-Design and Pages for Mac. Below are a few links to resources to help you prepare your poster. We also recommend you watch the APECS webinar by Kristin Timm about designing your poster... its really great because it talks about choosing a color scheme and fonts and all those fun things.
See here an example (APECS Poster).