GM - I too am in a similar position in switching careers. My situation is a little different in that I have been working within the HR umbrella for over thirteen years, but have been specializing in recruiting/staffing. You are correct in that HR can be a tough nut to crack. It is just as hard to change your specialty if you have become pigeon-holed within any one aspect of HR. You will need to exhaust every resource out there (headhunters included) on your job search. Certifications (PHR, SPHR via HRCI) are really helpful too, as most companies prefer their HR staff to come equipped with such designations. You may need to do some "cold-call networking" to get started too. Research companies in your area and try your best to identify the HR contacts at each. I have found that if you leave a message inquiring the advice of HR managers, they are likely to call you back if you craft your message as seeking advice - everyone likes to be an expert and experts like to tell you what they think about what you are doing and how you should do it. Through those contacts, you may be able to land an interview - remember to ask them if they can put you in touch with anyone they know who is hiring (in any case, always ask if you can send them your resume for future reference). Most importantly, keep those contacts for the long haul as you never know when they will come in handy down the road.  

Happy hunting!

- CWPA