Ales are usually ready to bottle in 2-3 weeks when fermentation has completely finished. There should be few, if any, bubbles coming through the airlock. Although 2-3 weeks may seem like a long time to wait, the flavor won't improve by bottling any earlier. Some books recommend bottling after the bubbling stops or in about 1 week; this is usually bad advice. It is not uncommon for fermentation to stop after 3-4 days and begin again a few days later due to a temperature change. If the beer is bottled before fermentation is complete, the beer will become over-carbonated and the pressure may exceed the bottle strength. Exploding bottles are a disaster (and messy to boot).