Can I take my iPhone 4 off the charger before it gets to 100 percent without it hurting the battery
Yes, you shouldn't charge it too much though. :)
Sure, I do it
yea you can just don't do it too much
Yea you can, but how can you hurt the battery? It has no feelings...
Yes. It's best to let it get below 20% then charge it to 100% but you don't have to do that every time. It won't hurt it if you put it on the charger early and if you need to take it off before it's fully charged it's no big deal.
Actually, I have an app that tells me to let my iPod die, then charge it to 100%, it's called battery magic, and it's useful.
As dean said - Just try not to remove it from the charger early to many times.