filling out suppliers forms doesnt sound too good to me. If the client is INTERESTED in your offering you should send them your application forms, T&C form etc and the client can then sign and return to you.
Alternatively, you can use email contracts/ agreements but i would rather a formal form/contact.
once the client signs up - you will need to get their jobs on your site, and i doubt very much they will manually post the jobs.
You need to be integrated with job posting systems, and you should also have your own job scraping technology.
you will need to make the contracts to suit your website / business. if you need help we have a consulting service and can help you make the contracts.
there are generally a few different contracts:
1. application form to use your website/ agree to T&C's - everyone must sign to post ads on your site/ create an account
2. free trial application form
3. monthly job deal agreement
4. CV Database agreement
5. banner advertising
it really depends on your business and what you offer.
HR directors are a good idea, but sometimes its better off to start small, ie with Senior Recruitment consultants, or Recruitment Managers, or even Marketing Managers.
You will need a very good sales pitch, think to yourself "why should the client use my site, what is their ROI"
sometimes even posting free ads is not good enough of a deal as it takes time for the company to get the ads posted.