Hi
I have posted a couple of designs (schematic and software) for building a lighthouse flasher (fade up, bright, fade down - delay). One designed is designed for low voltage (2 x AA) use outdoors and includes a light sensor to turn the flasher off during daylight, and a timer to turn it off after about 2 hours of darkness. The other design flashing constantly(about every 6 seconds) and is suitable for use on a layout.
More info at members.shaw.ca/Villy.Madsen
Villy