When you contact or are contacted by a recruiter, send a resume and other requested information, even if you make it clear that you are not interested in a current opportunity. Having your resume on file will make it more likely that the recruiter will call you again. If there are special circumstances surrounding your job search, tell your recruiter.
Recruiters deal with hundreds of applicants and understand discretion.
If you are seriously interested in getting a new job, you shouldn't be afraid to send out your resume. After all, the whole point of using a recruiter is to gain access to opportunities you would miss on your own. Tell the Truth - Don't EVER pad information or lie on your resume, on the phone, or in an interview. All recruiters have a universal loathing of candidates who lie, and they all have friends in the recruiting business. You may need the help of a recruiter in the future.