We have Hampton Bay ceiling fans installed on double (bipole) switches. Is there a way to use the existing wiring to provide separate control for the fan and the lights so we can put a dimmer on the lights? Or is there another way to dim the lights - would a remote do this?

You mean you have them on 3 way switches? You have a few different options.

1. Run a separate hot lead for the fan motor, and a separate switch for it.

2. Attach the fan motor to an unswitched hot lead and control it with the pullchain. Control the lights with the 3 way switches, you can make of one them a dimmer.

3. Install a remote control kit, and operate both the fan and light from the remote switch.

See:

Ceiling fan lighting - Ceiling Fans N More

Ceiling fan remote controls - help and FAQ- Ceiling Fans N More