+1
Are you actually trying to convert your bike to threadless, or do you just need a new fork? If the latter, you can try finding a threaded fork at the same length and diameter as your old one. This will be either 1" or 1 1/8" (diameter). If you wish to convert to threadless, you need a new headset and stem as well. And the steerer tube must be quite long to accommodate the new setup.