I don't think it's ever too early to have advisors, which is what I would call them. Especially if the project is in their area of expertise, very few people will turn down the opportunity to be an adviser to a brand new effort if you are truly serious about it.

The only real danger is expectations. You should talk about how much time the adviser can really spend on helping you. I've spoken with a number of professors and professionals that are advisers to companies that started to take advantage of their time and spoiled the relationship.

Also keep in mind that advisors are not employees. Unless you pay them someway (stock options, money) they are doing you a favor. If you think you'll need a lot of their time then plan to compensate them some way up front, even if you have to make good on it later.

Thanks for the advice.. I'll be sure to be clear on expectations, but I'm not sure how I can compensate him- I'm bootstrapping, and don't intend to raise funding.

In my personal experience, if you approach someone and tell them about what you are doing, you'll be able to gauge their interest level. If they are interested, it all starts from there.

I wrote about it in more detail on my blog:

http://startupsanddowns.blogspot.com/2011/04/only-n00bs-ask-...

As previously mentioned, make sure you limit the asks to reasonable, low-touch things, especially at first.

Also, most people won't say, "I'll give you advice, but it'll cost you X." If they do, run!!!

If you feel the need, just do it and ask him what do you need to get his help/mentoring.

I like this. I think he will too.