Thanks for the all responses here. One partner (me) not US citizen (based offshore - Caribbean). The other partner is US based. We will be doing business (design services) with both US and non US based companies.

@Paola Moreno so the question is should my partner incorporate in the state where they live (say California) or could they incorporate in another state (say Florida or Delaware) and not be double taxed? Does really matter for me as I'm based outside the US:-)