I have three futures in my kitchen . They have 2, 30 watt bulbs in them my wife says
They are to bright, and wants a dimmer on them . Question. Can I but a dimmer switch on them ,and where can I get one? They are fluorescent bulbs

I don't know that there are dimmers meant for fluorescent lights. You can buy CFL bulbs that will work with conventional dimmers. Just look around at the different ones on display for ones labeled to use with dimmers. I find Home Depot has a good selection of CFL bulbs at reasonable prices.

There are dimming fluorescent systems for most lamps that require special dimming ballasts and dimmers. These are somewhat expensive, and most likely only available special order from an electrical distributor.

Something that may help would be to change the existing lamps to a different "color". You most likely have cool white or 41K lamps. Look for warm white, soft white, or 35K lamps. These lamps will produce a softer warmer "color" light. Cool white can be harsh or too much "cool color" light.