Which Extracurricular is more significant - developing software programs for a business or attend a Pre-College Program at a elite College?

What ultimately matters is the knowledge that you acquire from either activities. You should be able to describe what you did while you were involved in the activities. Developing a software program for a business reflects your ability to apply your computing skills in real-life scenarios. Being accepted to and attending a pre-college program at an elite university shows that you are a competitive applicant who is seeking to broaden your horizons by taking college-level courses. It all boils down to how you explain why these matter to you and how you they will help achieve your goals.

Best,
Hari

Adding onto Srihari's comment, I will say that if attending a pre-college program at an elite college will put any financial strain on you and/or your family, then it shouldn't even be something you're considering. I say this for 2 reasons. Firstly, if a program really is competitive then it will have need-blind financial aid and if it does not then you should not be considering it (if it is a financial burden). Secondly, many pre-college programs aren't really all that completive and are used simply to make more money for the university, and applying to and attending these non-completive programs adds absolutely nothing to your application. As far as I know the 2 most famous and truly competitive pre-college programs are YYGS at Yale and RSI at MIT.

On the other hand, developing software programs for a business (especially if it is something really tangible that the business can vouch for, or something you can add on GitHub) then it is very very useful and will add a lot more to your application than any pre-college program would. Moreover, there are no downsides to doing something like this and putting it on your application.