A dimming ballast for CFLs
EssentiaLine 0-10V ballasts from Philips Lighting are compatible with daylight sensors or wall dimmers as well as fluorescent lamps and 0-to-10-V dimming controls. The ballasts are initially available in two-lamp T8 models with a .88 Ballast Factor and dim lamps from 100% down to 20% power. EssentiaLine ballasts meet all NEMA Premium and CSA energy efficiency requirements. Philips says they also are its first dimming ballasts in the North American market to be fully RoHS-compliant.
Here is the Philips news release: