Ales vs. Lagers
Ales and lagers are the two main styles of beer. Ales are the older of the two varieties, estimated to be thousands of years old. Ales are generally "top-fermented" at higher temperatures, may have flowery or fruity flavors, and be more malty or bitter. Lagers are "bottom-fermented" and typically take longer to produce. The slower process and lager yeast produces less by-products, and can mean a milder, crisper flavor.
Source: beer-faq.com
