Do not get under the car unless it is up on jack stands. They can be had for $15 so not using them is foolish in my opinion. Once it's up on the stands try to push the car off before crawling under. That should give you a more secure feeling.
I don't mean to be insulting with this question, but did you get the clamps off before trying to pull the hoses off? Mine came off quite easily and I can't imagine they could get "frozen" on. If all else fails you can cut the hose off right past the nipple. Make sure you have enough "play" left to reconnect though.