If you're just prototyping something for yourself I'm not sure it matters. The major reasons to be a corporation are:
* You have assets that you want to shield from liability when your customers sue you -- you'd rather have them sue the corporation instead. But, no customers yet = no problem yet. Assuming that your new idea doesn't involve radioactivity or anything.
* You want to give away shares in your new business to angel investors, VCs, or partners. No investors = no problem.
In any case, if you really think you want to form a corp you should talk to an accountant, and possibly a lawyer, about the details.
* You have assets that you want to shield from liability when your customers sue you -- you'd rather have them sue the corporation instead. But, no customers yet = no problem yet. Assuming that your new idea doesn't involve radioactivity or anything.
* You want to give away shares in your new business to angel investors, VCs, or partners. No investors = no problem.
In any case, if you really think you want to form a corp you should talk to an accountant, and possibly a lawyer, about the details.