I don't know if he is leading people to Hell. He might well be - I haven't visited his Church or met those who became professing Christians through his preaching. Do any of you know large numbers of professing Christians who visit his church? Are those who condemn "emergent types" actually friends with many "emergent types?" But I do know born again believers who have been blessed by some of what he has written and said, even if they don't agree with much of it. He asks some questions that are worth asking, and others that aren't.
Apart from Scripture, I've been blessed by what some ancient Catholic mystics have written. I've been inspired by some Celtic Christian writings. Some of the revelation of the spiritual life in there is mindblowing - and some is worth being wary of. But many protestants would damn these works and take anything pre-Reformatin as 'no go', apart from perhaps the writings of the earliest Church Fathers (though they were far from perfect, and often had their own strange ideas about Salvation, Heaven, Hell, Angels, Lucifer, etc.) I'm inspired in my walk with Christ by the love of women like Mother Theresa, who don't seem particularly desperate to preach on Hell. Mother Theresa even made one comment once that sounded like she didn't think people needed Jesus for salvation, but her writings, actions, and most of her other words reeked of the love of Christ. I know people have been inspired by her to make Jesus their Lord of and Saviour, despite her Catholic theology.
Though Rob Bell is nothing like Mother Theresa, and though I can see why he sends warning bells in people's hearts, this Hell issue isn't the only thing he talks about. His stuff called "Everything is Spiritual", for example, is really interesting - taking the latest findings of modern physics and science in general and revealing the majesty of the Christian God through them.
I know the above probably won't convince anyone. But for a start, I haven't seen him outright advocate universalism (I'd have to read the book to see if he does), and I have seen him proclaim Jesus as Messiah, Saviour, and King. I will say that the emergent church needs serious reforming, but I'm sure we as charismatics should understand how dodgy it is to brazenly state God is utterly not in a movement, just because it is different and currently very imperfect.