The answer to your question depends on a lot of factors and your conduct during and after your employment. If the first company requires you to sign a non-competition agreement then you might have a problem. However, even if the company does not require a non-compete you can still be liable for misappropriating trade secrets in certain circumstances. Additionally, some states have unfair and deceptive business practices statutes and laws which may be implicated in your situation depending on your conduct. I would especially be concerned given the fact that you are announcing your intentions prior to employment. In sum, I would err on the side of caution. Depending on the company you work for, it seems like you may be inviting an expensive lawsuit - even if you win. Just my two cents.
*disclaimer - nothing contained herein is to be considered legal advice or counsel.
Charles Gould, Esq.
Business, Employment and Non-Profit law