It seems the issue has been reasonably well covered, but I'll go ahead and toss in my perhaps superfluous thoughts on the matter.
At this stage, you have 2 types of intellectual property protecting your idea: a patent which doesn't exist yet, and a trade secret.
Everyone here is correct; no patent rights without an issued patent. How effective your application will be depends on (i) when it was filed and (ii) the substantive sufficiency of your application in protecting your idea. The former is set. The latter is impossible to tell from here. With respect to provisional applications, the latter consideration is where they tend to fall short. Many people who draft provisional applications seem to do so with the belief that the regular laws with respect to sufficiency of disclosure don't apply -- and that's a mistaken belief.
The important thing to note is that you may still have trade secret protection and that talking to potential licensees/purchasers will most likely cost you that trade secret protection (without NDAs at least). It may be wise to go that route, but you should understand what you're giving up and why.
The fact of the matter is that there's frequently a gap of protection between giving up your trade secret after filing your application and the issuance of your patent. You're at risk then. You have to weigh that against the risk your potential licensees would be exposed to in infringing your future patent. Part of the equation is the life-span of the product/service you invented. Products with short life spans could be entirely capitalized and exhausted before your patent ever issues -- think Millenium Bug novelty gifts and, if you were a conscious consumer in the 1970s, the pet rock. Some products have longer life spans but can be profitably capitalized in the few years your application is pending -- think about products that are easy to manufacture and can be flooded into markets very quickly, like articles of injected molded plastic. If your product is the type of thing that requires a huge investment that won't likely be recouped before your patent issues, you position is stronger.
If your invention represents a significant competitive advantage among your potential licensees and their competitors, you might be able to coopt the licensee in the effort to protect your idea. In other words, you can align your licensee's interests with your own vis-a-vis intellectual property. That would require some exclusivity of the proposed license and possibly an assignment.
I hope that helps.
Regards.