Ales are normally brewed with top-fermenting yeasts. The important distinction for ales is that they are fermented at higher temperatures and thus ferment more quickly than lagers.
Ale is typically fermented at temperatures between 15 and 24°C (60 and 75°F). At these temperatures, yeast produces significant amounts of esters and other secondary flavor and aroma products, and the result is often a beer with slightly “fruity” compounds, resembling but not limited to apple, pear, pineapple, banana, plum, or prune. Typical ales have a sweeter, fuller body than “lagers.”
A modern ale is commonly defined by the strain of yeast used and the fermenting temperature.
Info from Wikipedia.
Lagers main varieties
Light
Dark
Pale
Pilsner
Lager