I've been developping an application over the last year for a vertical market. I'm not done with it yet but at this stage it's already used by some companies.

Now here's the catch. A big company that has already develop solutions for that same vertical market is going to develop an application very similar to the one I've been working on.

Now how much should I panic here? Keep in mind that I'm a one man band and that this competitor company has a lot more resources than I.

What should be my next move? Approach that competitor to show them what I did so far hoping that they will make me an interesting offer. Offer that could be to get me to join them or get me to sell them what I did? Should I offer them my services because of all the things that I know so far about that solution?

Do you have suggestions on things to do so I won't be left with nothing in the long run? Is there a site that could give me more help on that? Is there a book that I could get?