Just the bulbs? I just replaced mine the other day and picked them up at the local auto parts place -- O'Reilley's. You should be able to find them at Autozone, Napa, or any car parts place. They were labeled '24'... made by Eiko -- that should be a standard bulb number. It's a 14v, 3.4w, wedge basebulb and works great -- perfect fit. It's rated 14 volts, 0.243 amps... so at 12 volts that's 3 watts (volts x amps = watts).
I think they were about $1 for a pack of 2.
For cross-references on bulbs I usually go to donsbulbs.com.