I am in an advanced stage of development of my game, I should hopefully release it in september/october.
I am thinking about putting a pre-order thing on my page, but I am dubious. This could provide me some feedback of what is people expectation: on the other hand I don't really know if it is a good idea to offer pre-ordering because I don't have a stable reputation (yet! ;) ) in games industry.

Of course pre-ordering game now would save a bit from the full price, as an incentive.

Has anyone ever tried that and with good results?

I'm not sure, but maybe offering a pre-order discount could help..

Personally, I do not think it is a good idea. You could easily end up ruining your reputation before it has begun.

Think about what could go wrong.
1) You don’t ship on time. This could really upset a customer.
2) You ship on time with an incomplete product because you did not want #1 to happen.
3) Your product changes due to unforeseen development issues and you ship something slightly different then what you promised.
4) You are unable to complete the project (medical, family, job issues).
5) You can’t locate the pre-sales purchase data when it is time to ship.
6) Your costs skyrocket and you end up shipping your pre-orders at a loss.

Think about what could go right.
1) You ship an excellent product on time that sells a million copies. Your pre-sales have done nothing but lower your revenue due to the necessary incentive.

I have pre-purchased only one piece of software in my life. It was from a company I trusted heavily with an excellent track record. I no longer deal with the company because of the problems that have occurred with the sale. In this case, the product ended up being late and cheaper to the people who did not pre-purchase.

Hehe yes, mpotter, you good some strong points here.
Only thing I don't understand is why there are a lot of commercial games that either ships unfinished, full of bugs, a lot different from the expectations, and still sell well!

Was joking of course! :D