I'd have the screen replaced first then sell it. I have to think it would be a much easier sell.
That said, it's worth noting which iOS version it's running, and if/if not it's jailbreakable/unlockable. If it's anything below 4.3.5, and if you have a baseband that's able to be unlocked, you can fetch upwards of $100 more. You wouldn't necessarily need to JB/unlock it, just simply express in the for-sale ad that it's possible.