Originally Posted by
SkyDog75
If the bike had a threaded fork, which has I'm guessing might be the case since you said "old", you can replace the fork with a plain ol' rigid fork. I've found that a lot of bike shops don't seem to carry them in stock for 26" wheels anymore, but you can order them from places like Niagara Cycle if need be. They start around $20. To get the right fork, you'll need a few measurements from your existing fork: the diameter of the steerer tube (1" or 1 1/8"), the length of the steerer tube, and the length of the threaded part of the steerer tube.
+1 on going with a rigid fork. I'll take a rigid fork over a cheap spring loaded fork any day. Check with you local bike co-op. Take the old fork along and match up type and length. You can buy suspension corrected forks which account for the front end drop from putting a load on your old suspension fork, but for a commuter, you may not want or need it, depending on what else you can find. Online you can find some hi-ten forks for $20-30 or chrome-moly for around $35-40.