Sometimes, when you are starting out, you don't consider all the possibilities...like if and when we bring on employees, do we want them to be owners? It's not really such a big deal. Typically, you, initially, authorize more shares than you issue. Regarding dilution, all that matters is what is issued. To set up an option pool you first need to put an Option Plan together that describes its term and conditions relative to vesting, exercise, etc., and sets aside a certain portion of authorized shares. You need to determine whether it will be used for just employees or for outsiders as well (contractors, advisors, etc.) or whether there will be separate plans for each. There are tax ramifications for the option holders, depending on the plan(s) you set up. Once you decide the basics, your corporate attorney should be able to easily put it together. However, so you're clear on this, options, typically come out of the authorized pool, not the issued pool. So existing shareholders need do nothing except approve the size of the pool. Options are really shares that could be issued, not shares that are. Once they are exercised, then they dilute existing shareholders equally. So, to keep simple, if the authorized shares are 1,000 and 500 have been issued to the founders and then an option pool of 50 shares is set up, and all these shares are, ultimately exercised, the total issued shares would be 550 and founders would have been equally diluted (accordingly to their shareholdings) by 9% (50/550). If less than 50 are exercised, the founders are diluted accordingly. And one last point on dilution. Number of shares or percentage are way less relevant than the value of those shares/percentage. So when you're looking to set up an option plan you should be expecting that the associated dilution will be made up in a corresponding increase in value that the employees will generate. That's a good business way to look at options.
Best bet, though, is to talk to your corporate counsel and your accountant to get both the legal and tax implications of an option plan.