This is the jumping-off point as you start to research your planet for your group presentation. I have listed some awesome links below, which will guide you to almost everything you need to know.
Remember to keep a list of the sites you use and include them on the "Resources" slide of your Keynote.
Have fun!
1) NASA Solar System Exploration
This is probably the best site I've found for complete information and images on our planets.
2) NASA Space Place
This website is loaded with links to different sites and interactives, where you can compare the diameters of planets, find the mass of your planet, and do other cool things. As you work through these sites, stay focused on gathering the information you need for your presentation!
3) Nine Planets Site
The info on this site isn't organized as well, and is somewhat more complex. But it's great information and definitely worth a look. Click on your planet to jump there or follow the links below the banner image.