Approaching day job's customers about startup?
hga: I think it really comes down to the degree in which your idea competes or potentially does so with the company you are currently work for.If it's completely unrelated ... to come up with something wild off the top of my head, say you've noticed something that could improve the landscaping you see as you go to the targets' front door, and your company sells business software of some sort, sure, go for it with care and the points that _delirium made.But if it's something you could suggest to the company you're working that they add to their lineup, then you really need to separate from it before pursuing this.  And states have very strong and enforceable laws about using the customer lists of your old company (note this doesn't have to be codified in your employment agreement), I'd consult a law library and lawyer for that.  And of course if you live outside of California you may have to wait a year or two for a non-compete to expire.