As you can see, that I have now added a few links that might help you if you are starting out in wargaming the Napoleonic’s period.
http://www.hat72.com/ is a plastic figure company that do many periods throughout history.
They also do different sizes, 20mm, 28mm and 35mm. Hat are a very good company and really cheap but the figure’s are of a very high quality. The amount of figures that they bring out each year is phenomenal. Well worth looking at before you buy from other companies.
http://www.mont-saint-jean.com/ is a fantastic site for information about regiments and their uniforms for the Battle of Waterloo. But like all uniform sites, they do differ from other book sources and websites.
The last one is http://www.plasticsoldierreview.com/ . This site will give you a look at all the 20mm plastic soldiers that are now out in model shops, from all the different plastic companies that are around the world. They give you information which could be valuable before you buy any figures for your army.