I don't use these guys, http://www.paystream.co.uk/
I have a "proper" face to face accountant.
However, my girlfriend who has started contracting in IT recently does and she is happy enough with them.
They do umbrella and ltd company routes.
My advice would be do the ltd company with them, get the jist of how it all works then find a decent accountant. I can pass you on to mine if you like. PM if so.