Not meaning to be facetious, but you could look at www.top-consultant.com for consulting jobs.
Other sites are www.consultantsboard.com and www.changeboard.com, or you could try any of the myriad IT industry boards.
All of the big IT consultancies have their own change management divisions. The question is which of those firms' projects and specialisms you want to be aligned to. The success of IT change management is closely related to the quality of the underlying products and solutions. If they don't work or you don't have confidence in them, your job will be much tougher.
For example, Accenture, CSC and EDS are crying out for good change managers to fill some critical roles in IT change management for their government projects. If you get a kick out of a challenging job, those could be perfect. Alternatively, if you don't like government projects and would like something based around clearcut solutions, there are firms like Deloitte or Hewitt that need change managers for implementing ERP systems.
With four years experience, you must have dealt with change projects before. Which firms have you had most contact with - what do your friends and colleagues think of the places they work?
Why is this so urgent and desperate anyway? Better to make a considered decision than to leap out of the fying pan into the fire, from one job you don't enjoy to another you're not suited to. You can also save a lot of interviewing time and rejections by selecting the firms with the best fit and applying in a more targeted manner.