Compact fluorescent bulbs are commonplace these days, but making them work with dimmer switches can be a challenge. Even "dimmable" CFLs have had problems with flickering, reduced dimming range and a shortened life span. Fortunately, companies like Lutron now offer dimmers specifically designed for this type of high-efficacy lighting.
The new line of Lutron C·L dimmers (which run about $30 each) have been redesigned to better accommodate the way CFLs and LEDs emit light, which is very different from that of incandescents. In addition to dimmable CFLs and LEDs, these dimmers also work with standard halogen and incandescents, providing great flexibility. They cost about $10 more than their incandescent-only counterparts, but a worthwhile upgrade considering the lifespan of CFLs and LEDs.
Lutron also offers lamp dimmers (above image) for lights that aren't wired to a switch. They cost about $10 and could be a great solution for rentals.