Two companies offering dimmable LED light bulbs.

When I first saw this bulb I thought: “I’d use this bulb without a lampshade so people can see how high tech it looks!” The SWITCH60 is a 60-watt equivalent bulb that uses about 12 watts of energy. (The 100-watt equivalent version uses 21 watts.) There are plenty of LED light bulbs out there already, but what makes this one different is that the bulb is filled with liquid silicone. That means it can stay cooler than other LED light bulbs - up to 40% better performance than air-cooled LED lamps, says the company. The SWITCH60 could pass for an incandescent bulb if it was under a shade. By now we’re probably all using energy-saving CFL (Compact Fluorescent Light) bulbs – yeah, the ones with strange shapes. They are super energy-efficient but most of them produce a fairly ugly bluish-tint light. LED lamps give off a much more pleasant light, but they tend to produce heat, especially the brighter ones that use more LEDs. Heat can shorten the life of the tricky electronics within the bulb. That’s what’s unique about the SWITCH60; the liquid-cooling silicone inside helps keep the 10 LED’s cool. (There are 12 LED's in the 100-watt version.) Although it looks similar to the shape of a 60-watt incandescent bulb, it is much heavier. (9.9 ounces on my Ultra-Ship Scale.) A advantage of this bulb is that it can be used with just about any dimmer. Some LED bulbs can’t be dimmed at all, or require special dimmers. In case you’re wondering (I was) if the bulb breaks, it won't explode. The company says silicone is used in certain food and cosmetic products. It’s a completely safe, food-grade product, non-toxic and non-staining.” And there’s no mercury in this bulb, which can’t be said about CFL bulbs. New technology isn’t cheap. SWITCH bulbs will retail for between $40 & $60 depending on wattage. There are 40, 60 and 100-watt versions. They’re in commercial installations now and coming in soon to the consumer market. 

http://www.switchlightingco.com/

Already in some stores like Wal-Mart is the 3M dimmable light bulb. Priced at about $25.